Data Types in C (part 2)

        Data Types in C.......

            Today, we will continue our discussion on integer data type. Our outline for today's would be to study modifiers such as short, long signed, unsigned and some programming examples. Long and Short These are the modifiers used to make it possible for a data type to take either less or more memory. Suppose if size of integer is of 4 bytes in your computer, then using short in front of integer makes it of 2 by tes.
    For example, In my computer size of short integer is of 2 bytes. you can see, the output is 2. On the other hand, using long as a modifier
 in front of integer allows integer data type to take more memory space.
     Here you can see, size of long integer is of 8 bytes. 
      Note: It is not guaranteed that short takes lesser memory than the integer and long takes more memory than an integer. The only thing which is guaranteed is that, size of short is less than or equal to size of integer and is less than or equal to size of long As I already told you
 in the previous lecture, that integers can have signed range and unsigned range. Typically signed range is from -32768 to +32767 and the unsigned range is from 0 to 65535 for 2 bytes integer. And for 4 bytes, this would be the range This is because in reality, most of the times along with the positive values there is a need of representing 
negative values as well.
      For example: When you are performing subtraction of 49 with 50, you will get -1 as the answer. For representing these negative values in computer, you have different representations and one of the widely used representation is 2's complement representation. Range of negative numbers comes from this representation only. Apart form this that, there is one more important point that we need to know.
       When you are declaring integer, with some variable name then it is by default a signed integer variable By putting unsigned modifier, in front of integer it allows only positive 
values to be assigned to it.
    Lets see what happens when we are trying to use these modifiers in front of integer data type. I am going to provide 4 programming examples that will print the range of integers when we apply different modifiers in front of integer data type.
      Here is the first example. First of all, I have included a new header file ……. limits.h This header file consists of some symbolic constants
that are useful in determining the minimum as well as the maximum values of any data type according to the system. In this example, I have used symbolic constant
              INT_MIN
and assigned it to variable 1. This symbolic constant gives me the minimum value of the signed integer according to my system. And similarly, 
       INT_MAX
is assigned to variable 2 and this will give me the 
maximum value of signed integer. Here, in this example we are trying to print the range of signed integer writing int or signed int, both are one and the same thing, as I already told you. because, by default integer is signed integer in our systems.
     In my system, the size of integer is of 4 bytes. Therefore, range of signed integer is from -2147483648 to +2147483647. In the second example, we are trying to print the range of unsigned integers. here symbolic constant, maximum value of unsigned integer is UINT_MAX.
      Also, there is no symbolic constant available in limits.h header file, for minimum value of unsigned integer. Because minimum value is fixed for all systems and that is zero. And there is one more important thing to note Here to print the value of an unsigned integer, we have to use %u
instead of %d.
       As %d is used to print decimal value, %u is used to print unsigned decimal value. Now as we can see, the output is range of unsigned integer is from 0 to 4294967295. As for 4 bytes or 32 bits unsigned integer maximum value is 2 raised to the power 32 – 1 which is 4294967295.In the third example, we want to print the range of short signed integer. Symbolic constants for 
getting the minimum as well as the maximum values of short signed integer is SHRT_MIN and SHRT_MAX respectively. Because of this "short" key word, integer data type takes 2 bytes
instead of 4 bytes.
       Therefore range would be from -32768 to +32767. And finally, in example no. 4 we are using USHRT_MAX for getting the maximum value
of unsigned short integer. And as expected,
the range is from 0 to 65535.
        Note: You can also write unsigned short instead of short unsigned here. The order doesn't matter.
       You can also check the range of long integers
by replacing the keyword short with long.
And in printf instead of using %d, you can use %ld for long signed integer and instead of %u
you have to use %lu. There is one more thing called long long integer. It simply means,
Suppose if long integer is of 4 bytes, then long long integer will be of 8 bytes else if long integer is of 8 bytes, then long long integer would be of 8 bytes only. Because the maximum limit is upto 8 bytes you can say.
         Let's try to summarize the information that whatever we had learnt till now. sizeof(short) is less than or equal to sizeof(int) and is less than 
or equal to sizeof(long) Writing signed int some_variable_name; is equivalent to writing
int some_variable_name;
%d is used to print "signed integer"
%u is used to print "unsigned integer"
%ld is used to print "long integer"
which is actually equivalent to signed long integer.
%lu is used to print "unsigned long integer"
%lld is used to print "long long integer"
%llu is used to print  "unsigned long long integer"
OK friends, this is it for now…….

Data Types In C (part 1)

          

Data Types in C...
        

          Today we are going to learn about a  fundamental Data Type called integer. we have various data types to study. And today we begin our session with integer Data Type. Recall from . introduction to variables. Integer can take either 2 bytes of memory space or 4 bytes of memory space, depending upon the machine you're working with. 
      we know 1 byte is equal to 8 bits, therefore 2 bytes equals to 16 bits and 4 bytes is equal to 32 bits. More the size more content it can hold. Obviously, if you want to know the size of integer programmatically, then you can by using "sizeof" operator.
       "sizeof" is a unary operator that helps us in determining the size of any data type that we provide to it. As you can see here in my computer, "sizeof" integer is actually equal to four bytes as the output is 4 of this "sizeof". I provided the output with the help of this printf function.      
          Note:"sizeof" is a unary operator and not a function. You might think of it as a function, but it is not a function. Now let's define "Range". Range is nothing but upper and lower limit of some set of data. For example, here you can see this set consists of some values {0, 1, 2, 3, 4}. If you want to determine the range of this set of data, then you have to determine the minimum value as well as the maximum value.
         Here, you can see the minimum value is 0 and the maximum value is equals to 4. Therefore, the ranges from 0 to 4. As you can see in this set of data, there is no value which is less than 0, and there is no value which is greater than 4. And that is what the definition of "Range" is.
       Now, before diving deep into the concept of range of integers, it is better to get into some prerequisites. And one of the prerequisites that we have to pass through is knowing Decimal number system. In our day to day life, we use Decimal number system for many purposes. Maybe for counting purpose, or maybe when we need to quantize some information like 2 apples, 30 bananas, and so on. Decimal number system is human understandable number system. and is also called as base 10 number system. "base 10 simply means the range of number that we are available with is from 0 to 9.
          Let's take one example of a decimal number. We pronounce this number as five hundred and sixty-eight. Instead of simply saying 568. Have you ever wonder why do we pronounce it like that way? Because in reality, we have numbers ranging from 0 to 9. And if you want to represent such a large number, we have to multiply each digit with their respective place values. Here place value are starting from the rightmost end, and it is 10 raise to the power 0, then 10 raise to the power 1, then 10  raise to the power 2, and so on.
        When we multiply 8 with 10 raise to the power 0, we get 8 only. When we multiply 6 with 10 raise to the power 1 we get 60. When we multiply 5 with 10 raise to the power 2, we get 500. And now, in order to get the desired result, we add them up to get 568 as our result. 
        Isn't that easy? Okay! But this is not something that machine could understand. It has its own number system called Binary number ssystem.Binary number system is machine understandable number system, and is also called as base 2 number system. Means range is from 0 to 1. Only two numbers. As you can see, here, I've written a four bit data 1 1 0 0. In this case, also each digit must also have some place values associated with them. Because binary number system has base is equals to 2. Therefore starting from the rightmost end we have 2 raise to the power 0, 2 raise to the power 1, 2 raise to the power 2 2 raise to the power 3 as their place values. And if you want to represent this number in decimal, then you have to follow the same method that we had adopted in case of decimal number system i.e multiplying the digits with their respective place values, and finally add them up.
          As you can see here, if I multiply 2 raise to the power 0 with 0, I get 0. 2 raise to the power 1 with 1, I get 0. 2 raise to the power 2 with 1 I get 2 raise to the power 2 which is equals to 4. 2 raise to the power 3 multiplied with 1 I get 2 raise to the power 3 and that is equals to 8. By adding all these numbers, we get 12 as our answer.
        Now what would be the range of 4 bit data? As we know, know to calculate range of any number, we have to know its minimum, as well      as maximum value. For 4 bit data, minimum value is equals to 0. When all digits are 0. And maximum value is equals to 15 when all digits are equals to 1. You can get this value by using the same method by multiplying each digit with their respective place values and finally add them up. In this case of maximum value you're multiplying 2 raise to the power 3 with 1, then 2 raise to the power 2 with 1, 2 raise to the power 1 with 1 and 2 raise to the power 0 with 1 and finally add them up to get the answer 15. And here because all of them are zero multiplying it with their respective place values would finally give the answer is equals to 0.
          Therefore, range of all the data is from 0 to 15 only. But there's one more formula available to calculate the maximum value. And that is, 2 raise to the power n minus 1. Suppose you have a 32-bit data, then adding all these place values multiplying with their digits is quite difficult, then this formula is quite handy to apply. Here, by replacing n is equals to 4 for 4 bit data, you get 2 raise to the power 4 minus 1 which is 16 minus 1, and that finally gives the values equals to 15, which is our maximum value. 
             Let's calculate the range of integer. If in your machine, the size of integer is of 2 bytes, then the unsigned range is from 0 to 65 535. By applying the same formula for calculating the maximum value. By replacing n with 16, you get 2 raise to the power 16 minus 1 which is nothing but 65 535. Usually, you also have to represent the negative values. And that we can do with the help of 2's compliment representation. We actually have three different representations to represent negative numbers, and they are signed magnitude, 1's compliment and 2's compliment. But in most of the computers 2's compliment representation is used. 2's compliment range is from -2 raise to the power n-1 to +2 raise to the power n-1 minus 1.
       If you want to know more about 2's compliment representation and other representations, then you can refer the Neso Academy playlist of "Digital Electronics" here on YouTube. Here, you can see -2 raise to the power n-1. By replacing n is equals to 16 I get 2 raise to the power 15 which is -32 768 and +2 raise to the power n-1 i.e. 2 raise to the power 15 minus 1 that gives 32 767.
       On the other hand if your PC supports 4 bytes integer, then Unsigned range is from 0 to 4 294 967 295. By applying the same formula for the maximum value, Signed range can be obtained by using this 2's compliment range. That's it. See you later…..

Rules of Declaring a Variable.....

      Some Of The Important Rules To Declare VARIABLES In C.........


                    C follows some naming conventions Or you can say rules for naming their Variables. the need for making this information separately is that this is one Of the most avoidable topics while Learning C programming because we Usually don’t care how we name our Variables as it is not the case that Everything is allowed in C programming......
        As we want therefore studying naming Conventions is equally important name Of a variable is composed of letters or Maybe the combination of letters both Uppercase and lowercase and digits rules For naming variables are as follows you Cannot start your variable name with a Digit for example globe is a valid Variable name on the other hand to Globe is invalid even though underscore Counts as a letter but don’t begin Variable names with underscore although You cannot begin with underscore because Huge number of variable names beginning With underscore are resolved for system Use using them in your program may cause Problems in your code execution  it’s better to avoid such Names C language is case sensitive means Uppercase and lowercase letters are Distinctive writing.
      You can also assign variable to a variable instead of this constant value 3 or 4.int var1 is equal to 3. Suppose my new variable is var1,I declare another variable var2 and I initialized or you can say I assigned value to it  with the value of var1.Here you can see that I am assigning the value of 3 actually because writing the name of the variable means that I am assigning its constant value and I'm assigning it to variable 2. Lets print it using printf.Lets debug As expected, the output turns out to be 3.You can also assign same values to different  variables in a single line.As you can see I declared and defined variables in the same line using the same data type.All these variables are of integer type.Instead  of defining and declaring in different lines it is better to write them down  in a single line.Suppose I assign them the value equal to 4 all in the same  line and then I print it.
        Lets build and run.And as expected we get the value 4 4 4 because we had printed three times.There are three different variables var1 var2 var3. Because all of them has been assigned to the same value 4 That is why we are getting three values of 4 in the output. 
         Where all are different you can say It is interesting to know that Traditionally lowercase letters are used For naming the variables and uppercase Letters for naming symbolic constants Will talk about symbolic constants when  We study the use of hash define later Special characters such as at the rate Hound percentile power ampersand star Etcetera other than underscore are not Allowed in the name of variables note Maybe some special characters use in Naming variable can work but most of Them failed like when I put dollars Somewhere in between or even at the Beginning of the variable name it works But if I choose some other special Character like percentile it produces Error therefore battle is to avoid the Use of special characters but yes I told You to avoid using underscore at the Beginning but you can use it in between The name of the variables blanks or you Can say white spaces are not allowed in Between for the separation of different Parts of the name of variable. 
         for Example in my variable is invalid Because of the blank space over here you Can see blank space compiler won’t be Able to recognize it as a single Variable instead if you want to improve Readability you can use underscore Instead of blank space int my variable Is now a valid variable name as you can See over here now I’d put underscore Instead of that blank space keyword Slight if-else for wild switch int float Long double etc are result words you Cannot use them in naming your variables Although all these keywords are Lowercase and if you insist to use them In naming your variables you can make Either a Or multiple letters uppercase and then You can use them like this finally there Is one important tip do not use longed Name for your variables it may not look Good and using them later in your Program is not that easy because you Have to write down those long names Again and again in your code whenever You want to use them that’s it for now See you in the next lecture.

Variable (part 1)

    


  

     

                               variable in c...

  In today's lesson,we are going to talk about variables in C programming. Think of a glass of water.If you want to drink some water, then you put water inside glass and drink it. You can think of a variable as a glass of water.As a glass can store water in it similarly variables can store some value in it.After storing  the value,you are free to use this  value in your program.

           In reality, variables are simply names that points to some memory  location.Thanks to the inventor of C language who makes it easy for us to store values in memory by simply using the name of our choice.You don't need to worry about at which location of the memory your value is stored. Your task is to just provide the name and internally it will point to some memory location.But there is one thing that we need to be sure about.You must have to declare variables before using it in your program.Declaration simple means,announcing the properties of the variable to the compiler. Here, by saying properties we mean that what will be the size of the variable and what will be the name of  the variable Don't worry, it is not a very difficult job to do.You will see in a moment how easy it is to declare a variable.

      There is one more term called definition of a variable,which means allocating memory to a variable.Most of the time declaration and definition will be done at the same time.But this is not always the case.It depends on the modifiers you had mentioned with the variables. We will talk about modifiers later and then we will also explain how declaration and definition is different for different modmodifier Let me give you an example of how to declare a variable.Here, the name of the variable is var and it has an  integer data type.Data type simply means how much space a variable is going to occupy in the memory.Therefore by writing....... int var you are declaring a variable along with that you are requesting the compiler to allocate memory for this variable.  Please note down on one thing here after int varwe have put a semicolon over here.This is very important.Because this is how your compiler separates one statement from the other.So don't forget to add a semicolon at the end of the variable.

     Now, the memory location depends upon the type you use Here because in our example,we are using integer data type therefore it may take either two  bytes of memory or may be four bytes of memory.It purely depends on the system you are working on. Again you  don't have to worry about how much space is allocated to your variable.You only have to concentrate on the declaration and definition of the variable If you assign some value to a variable,at the time of declaration itself Then this thing is called initialization.This is how you will do initialization. Note- initialization of a variable doesn't mean that you cannot change the value of a variable afterwards in your code.If you want the value to be changed somewhere,then you can do that this clearly captures the meaning of variable.Variable in its pronunciation has word vary.Something that can vary over time.On the other  hand constant is just the opposite.once defined will never change. 

                  Let's see how we can change the value of the variable after  initialization.Let me write down the code here.I am writing .........#include that is our header file because we have to print some output. Then I am declaring main function.Inside this main function,I'm first declaring a variable named var.Suppose I initialize it first to 3,and afterwards I change this value to 4.You can observe that again I have not written int var in this statement when I'm assigning value to it.because the memory is allocated to the variable once and defining it once again means you want to allocate memory again for the same name. And this is illegal.Note- each variable must be defined only once but it can be used multiple times with different assignment in your program.But there is one exception as well.when we study scope rules later you will understand that same variable name can be defined in different blocks of code.You will slowly understand what does it mean.For now it is enough to know that inside this main function you cannot define multiple variables with the same name.Then suppose we write,printf with %d and we print the value of the variable.I will explain you more about what this %d means.For now, I can only tell you that this will print the  contents of whatever is there inside this variable var you have to put at  the end return 0 Let me save this.And build and run the code.You can see the output here which is 4. Previously I had initialized the Value of 3, and then changed it to 4 and print it.And as expected,my output is equal to 4 without any error.

               You can also assign variable to a variable instead of this constant value 3 or 4.int var1 is equal to 3. Suppose my new variable is var1,I declare another variable var2 and I initialized or you can say I assigned value to it  with the value of var1.Here you can see that I am assigning the value of 3 actually because writing the name of the variable means that I am assigning its constant value and I'm assigning it to variable 2. Lets print it using printf.Lets debug As expected, the output turns out to be 3.You can also assign same values to different  variables in a single line.As you can see I declared and defined variables in the same line using the same data type.All these variables are of integer type.Instead  of defining and declaring in different lines it is better to write them down  in a single line.Suppose I assign them the value equal to 4 all in the same  line and then I print it.

            Lets build and run.And as expected we get the value 4 4 4 because we had printed three times.There are three different variables var1 var2 var3. Because all of them has been assigned to the same value 4 That is why we are getting three values of 4 in the output. 


Constant In C (part 2)

 


      

                                        constants in c

  Let us discuss now character constraints these are also two types single character and string string constant what is single character constants if i write like suppose single character is a so you will write like this in single quotation so this is what character constant constant so you can say character constant is what it is having a single character enclosed within single quote marks this is character constant this is also character constant and suppose i write this backslash this one zero this is also character constant these are backs backslash character constraints these are having different meanings there is list of backslash character constants right those are having different meanings fine and you can say like if you write this one comma this is also character constant right and if you write this at the rate this is also character constant so any single character which is enclosed within these single quotation mark within this you can also write down some characters also like a b c d capital a b c d or some numbers and some special characters also those are character constraints and these character constraints are within computer it these are being stored in the form of sky codes right like uh here this a means 97 capital a means what 65 like this small b means 98 and like this capital b means 66 and like this so on right and these are also having uh their different this this value this is also character constant if you write 1 and see 5 is not equal to this 5 this is character constant it is having some different value this is numeric constant this you need to take care right if you are writing anything between these single quotes the number then that is character constant that is not numeric constant this is not integer constant fine so sky value i am writing here you can see so these are sky values capital a to z 65 to 90 small a to z 97 to 122 zero to nine numbers are having a sky value 48 to 57 and some special character like this um coma or at the rate or some special characters are having values from 0 to 47 then 58 to 64 and 91 to 96 right you can also check out like which special character is having between these lie between these values and between these and between these you can google it out right but you have to take care of this thing and you can also perform some arithmetic operations on these character constants right suppose i am printing uh thissee if you are writing like this percentage printf percentage d this is for integer format specifier and a it is what single quote mark so this is what character constant so it will print what integer value of this a because i am writing here format specifier percentage d this is for integer this is to print integer value right here if you compiler will find it is percentage d then it will print what whatever is given here after this coma the first one the first one for that it will print the decimal value means that that integer value the integer value of a is 97 so it will print 97 and if you write percentage c it is what character constant it is used to print characters and if you write here 97 then it will print the equivalent value character value of this 97 fine and see every character is having integer value that is why i am saying that you can also perform arithmetic operations on character constants right next comes to string constant so string constants are you can say sequence of characters enclosed within double

                  characters and enclosed within double quote mark so this is string constant if you write abc this is what string constant and these characters may be letters number some special characters space everything if i write like uh here a b dollar this is also string constant but here c one thing if i write a in double quote this is not it is single character but enclosed in double quotation mark so it is not character single character constant it is a string constant and if i write a this is what single character constant but these are not equal this is different thing this is different thing this you need to take care this is string constant this is what character single character constant fine and if i write like 1 2 3 4 5 in double quote this is also string constant right but here this like 1 is not equal to this one because this is single character and it is equivalent to its sky value of 1 is 49 but string constant this is not equal to its sky value this is string constant right so you need to take care of this thing also and whenever this string constant is there in a program and when compiler read this string constant then what compiler will do compiler will store the address of the first character reads the address of the first character and it will append a null character constant it will append a null character constant at last why so just to mark this is end of the screw end of this string right so length of the string is what one two three four five six here if you find out the length of this string then it is not five it should be six because a compiler has added null character just to mark that this is end of this string fine so now let us discuss how to declare constants in your program we use what keyword const keyword to declare constant like this right one method is this one so if you write in a program suppose i am writing a function word main i am not writing a complete program you can include those header files and i am writing here const int a value is 10 in this program right means this value of a is constant throughout the program you cannot change this value if suppose you will print this value a then always the output would be 10 and suppose after that i am writing a is equal to 50. you are trying to change the value of a then it this line will give error that this value is you can say its read only value you cannot change this value because you have written conest keyword before this declaration before this initialization of this variable this is variable name that also will discuss what are variables in c this is data type but if you write like this into a is equal to 10 fine when you will print value of a 10 would be printed but after that anywhere in a program you can change this value if you write a is equal to 50 and then if you print value of a then the updated value would be printed 50 now you can change this value this will not give error so you have to declare constant using const keyword right another thing it that i have discussed in starting of this video you can use hash define macro definition symbolic constant so there you can write this would be above this main although you can use anywhere the hash define statement but generally we use where above this main function right so we write like what hash define suppose i am writing a 10 this is also fine right but generally here we write what capital uh letters only like if you're writing pi then pi also if you write max then max also like this right and why i am using these capital letters so that you can distinguish between the normal variables within the programs and the symbolic constraints that is why there are some rules when you use this hash define statement then there are some rules to write this the statements and what are those rules there should not be any space between hash and define there should also be a space between hash define this and then name of that constant and then value of that constant another thing you cannot use here equal to right this would be wrong fine you cannot use semicolon after a statement. 


Constant in c (part 1)

     

          

                                  constants in c.....

 In c constants are having fixed values the value of constants are not going to be changedt hroughout the programmer you can sayd uring the execution of a program the values are to be fixed the programmer while writing a program will specify these values means compiler know the value of constant during compile time you will not give the value at runtime right one thing is what we use symbolic

      constants so that we use to define some fixed values like suppose um value of pi so you will write hash define pi is 3.14 this is what that definition section we have discussed when we were discussing structure of a c program so the value of pi is fixed 3.14 it is symbolic constant if you write hash define suppose max value is 50. so the value of that max is what is to be 50 throughout the program it is not going to be change you cannot change that value these are symbolic constants right so we are having basically two types of constants in c

1] numeric constants 

2] character constants

or somewhere it is also written four types of 

1] constant integer 

2] floating point constant

3] character constant 

4]string constant

     let us discuss so these are four types of constant or you can say two types numeric and character constant is numeric is further divided into two types integer constant and real constant of floating constant here single character constant string constant so basically four types so let us discuss first one is integer constants these are having decimal values like if you write this uh 10 it is it is a constant five integer constant one integer constant integer constant right these are valid but if you write 0 5 this is not you can say decimal constant see in integer also we have 3 types decimal constant octal constant and hexadecimal constraint right decimal means we can use uh the the numbers from 0 to 9 base is 10 octal constant means from 0 to 7 base is 8 and hexadecimal means we can use from 0 to 15 and bases base of these constants are 16 so integer also having three categories so if you write 0 5 that comes under ah octal constant because the rule is what octal constants starts with the value 0 always right but decimal constant means yeah you can use 0 but if there are two digit in that constant so 0 can be at this side right side but 0 cannot be at this side left side if you write like this this comes under category octal constant right and constants are also called literals right so here also you can we can express an integer in three forms decimal octal and hexadecimal and by default if we say integer constant generally by default we represent that in decimal constant not octal not hexadecimal right difference i have told you what is octal now how you write hexadecimal constant c in hexadecimal we have sequence of digits preceded by either 0 x or you can say 0 small x

    let us suppose i write ah 0 x this is what hexadecimal constant right and see in hexadecimal we use what from 0 to 9 numbers and a to f characters i have told i have written here 0 to 15 but here we use from 0 to9 numbers 10 numbers like right and after that 5 is what alphabets a to f right.

    so here you can say a means 10 0 to 9 we use numbers 10 numbers then b like this we are having from 0 to 15 0 to 9 numbers and then 10 to 15 we represent like abcdef so if i write 0x that is also exactly decimal constant if i write like 0 x and 7 If this is also hexadecimal constant but if you write 0 x and suppose i am i am writing 7 g this is not hexadecimal constant because we cannot use g we can use only a to f right so you can say these integer constants are sequence of digits suppose i am writing here one two three four this is also what integer constant but rule or what you cannot write like this 56 comma 100 you cannot write any comma or special character between these constants so this is not valid this is invalid constant integer constant right or if and by default the sign is what plus you can also use sine plus or by default x plus if i write minus 1 to 3 this is also valid so you can write a sign either minus 1 plus if you write like this dollar one two three this is incorrect you cannot use any special character you can you you cannot use any comma you cannot use any spacel ike fifty seven space hundred this is also invalid you cannot use space uh between these sequence of digits this there should not be any space any commas any special character this is valid one two three four or like 56 or five six seven eight this is also valid right so now i hope you got integer constant let us discuss real constants so real constants are also known as floating point constants these are having fractional part like if you uh write 12.56 this is decimal part this is you can say you can say this is what the integer part this is decimal point and this is fractional part so having decimal point these are what real constants so if i write plus this that is also fine if i write minus 50 . 6.02 that is also fine sine can be plus or minus by default sign is plus right but if you write this is invalid there cannot be two decimal points right and you can also represent these uh decimal points or these floating point constant in uh exponential form having mantissa then e then exponent mantissa can be anything like having that decimal point and exponent is always constant right so these are some examples see which one is valid constant or numeric constant or not this one is valid 0x this is also valid This is not valid this one this is not valid because here we have space 0 1 2 this is valid 1 2 3 yes this is valid right and if suppose i write 0x af this is also valid and suppose if I write hash one two three this is invalid you cannot use any special character or known digit character right so these are numeric constant.


Introduction To C programming - 1

         

                                Introduction to c programming



   The c character set

C language uses the uppercase letters A to Z, the lowercase letters a to z, the digits 0 to 9
   Special characters
   + - *  /  %  &  #  !  ?  ^  {  }  (   )  :  ;  ?  =  ,  <  >  (blank space)
Most versions of the language also allow certain other characters, such as @ and S, to be included with strings and comments.
            C program uses certain combinations of these characters, such as 
      \b = backspace
      \n = newline
      \t = Tab
These character combinations are known as escape sequences
Example of c pprogram… . 
Question- write a c program to print a hello word ?         
 Ans-  
    #include < studio.h>
     Main () 
   {
    Printf (“ Hello word “ ) ;
   }
This is very simple program  used  to print the message hello word  on the output screen. 
 1st line of program # is a compiler directive. 2nd line  uses a special word main, which denotes the starting point for execution of the program… All program start their exaction from main. Printf is a only executable statement in above program. This is use to display any message on the screen. 
  Any message written within double quotes of the printf statement is displayed as it is. But one ma note the absence of \n in the output, although this was also included within the double quotes. \n is act ally a special character (known as escape sequence), which corresponds to newline character. Inclusion of \n in double quotes means that cursor should be shifted to start of next line. If you see carefully the output

screen above, the cursor position (shown as =) can be noticed at the start of next line. Had this statement

been written as
printf("Hello \n word ) ;
The output screen would have been different. And looked as 
    Hello
    Word
It may be noted that C programming gets shifted to next line now. Reason for that is the changed position of \n in the modified printf statement. But the cursor remains in the same line now just after the last alphabet  of the displayed message as there is no new line character at the end of the message. This will affected the next output when you rexecute the same program. 
  The semi colon (;) is a must after completion of every statement (end of any line does not necessarily mean completion of a statement). In the above example, semi colon has been put after printf statement, denoting its completion. It is worth noting that all instructions related to C program have been written in lowercase. Remember C is case-sensitive language and thus, any lowercase character cannot be used as uppercase or vice versa. Most of the instructions of C are written in lowercase. 

IDENTIFIERS AND KEYWORDS


Identifiers are names that are given to various program elements, such as variables, functions and arrays. Identi- fiers consist of letters and digits, in any order, except that the first character must be a letter. Both upper- and lowercase letters are permitted, though common usage favors the use of lowercase letters for most types of identifiers. Upper- and lowercase letters are not interchangeable (i.e., an uppercase letter is not equivalent to the corresponding lowercase letter.) The underscore character (_) can also be included, and is considered to be a letter. An underscore is often used in the middle of an identifier. An identifier may also begin with an underscore, though this is rarely done in practice.    
   The standard keyword are 
There are certain reserved words, called keywords, that have standard, predefined meanings in C. These keywords can be used only for their intended purpose; they cannot be used as programmer-defined identifiers. The standard keywords are
1]auto
 2] extern
3] static
3] break
4] Floatn 
5] for
6] case
7] switch
8] char
9] goto
10] typedef
11] const
12] if
13] union
14] continue
15] int
16] default
17] long
18] unsigned
19] do
20] register
21] void
22] double
23] return
24] volatile
25] else
26] short
27] while
28] enum
29] signed
30] sizeof

 also include some or all of the following keywords.
1]ada
2] far
3] near
4] asm
5] fortran
6] pascal
7] entry
8] huge

linux

Linux.......
hello and welcome to the techisagar
in today's.. I will give you guys
a quick introduction to Linux and
I'm gonna show you how to use some
very useful introductory Linux
commands using a terminal window
now just to be clear this is a course
for beginners who want to learn how to
use command on a Linux terminal now
for those of you guys who are not
familiar with Linux at all let's give
you a quick perspective Linux is
not Unix UNIX was created by a bunch
of AT&T employees in 1969 Linux was
written by a name AGGA by a guy named
Linus travolt who created the entire
thing by himself and released it
around 1991 now Linux is a powerful
operating system but it is especially
designed for server systems and 90% of
the world's fastest computers like
supercomputers run on some form of
Linux and this is because a rock-solid
system okay so that was a quick history
on Linux that was just to give you a
perspective now Linux and UNIX are
different just remember that now one
more thing before we dive in Linux
comes in many different varieties
which are called distros or
distributions in this tutorial we
will Use the popular Ubuntu
distribution of Linux but there are
others out there as well such as
Fedora mint and Debian and more even
Android is a Linux distribution so the
basic commands we will rerun it we will be running and learning today can be generally used on almost all different Linux distributions alright so let me go ahead and launch Linux and I just wanna let you know I'm running Linux on my Windows so what you do is you install VirtualBox which is right here so let me launch that and inside a virtual box you can install any operating system possible so I have put Ubuntu Linux in side of VirtualBox on my Windows 7 machine ok so let me run this up and I just wanna let you know you can actually find a link in the description below which tells you how to install VirtualBox and Linux on your windows 7 . if you want to go ahead and do that but this is the Ubuntu Linux that is launching right now ok so here you're looking at bound to Linux and before we dive into the commands I'm going to show you something real quick what you're seeing here all these icons all this desktop all this nice graphical features this is called the GUI GUI this is called the graphical user interface now we're not worried about that today what we're worried about is the CLI which is called a command line interface so you have to launch a terminal to go into the command line interface and then once you are search for an app you can type in terminal which brings up the terminal right here and then you can actually click that and that is the terminal we will be working with all right so the first command we will be looking at today is the PWD command oops it's not typing okay p WD command PWD command stands for print working directory so when I press ENTER it actually tells me which directory I am currently located at so if I go to my own folder browser I am actually in home sake which is right here so I'm looking at all these guys on my command prompt. now the second command I want to show you guys is the LS command when you press LS it gives you a listing of everything which is in the current directory so the current directory is the sake directory which is my username and under home inside of home I've got all these guys so I've got the desktop downloads music public videos and if you come over here that's all the same stuff you're gonna see in a regular File Explorer so here's the desktop documents downloads music same stuff that you see here so that is the LS command it's it's it stands for list and when you list it lists whatever is inside of your current directory again PWD stands for print working directory so it tells you where you are currently located in now as you can see when you have a pretty graphical user interface you can see everything right in front of you but if you have a command line interface like this one a terminal you're not gonna be able to see anything so if I clear this that's all you see so you have no idea where you are okay so to see where you are PWD to see what you have at where you are you type in list now the next command I'm going to show you is called a CD command and CD command has a lot of variations CD is used for navigation so let's say I want to go to the Downloads folder. how do I go there I type in CD and I type in downloads the name of the folder and just remember
everything has to be exactly as it appears so the in in Linux everything is case-sensitive so this cannot be a small d it has to be capitalized just like it is here okay so if I type in CD downloads now I am in the downloads folder okay and how do I know I'm in downloads folder PWD it actually tells you right here so I'm in home slash sake / downloads okay and let's see what we have in downloads right now type in list and there's nothing in downloads so that's all launch this again go to downloads and as you can see download directory is actually empty okay so if it is empty you're not gonna see anything here now let's say I want to go back to my home directory my sake directory how do I go back so CD takes you into a folder and if you want to go out what you do is you type in CD space two dots and that takes you back to the previous directory that you were focused on now if you want to go to the root directory which is like in Windows it's like the C directory what you type is CD forward slash make sure you put the space okay so CD space forward slash press Enter and that's gonna take you to the root directory. let's type in LS and as you can see the root directory has much more than your user directory okay again but home and sake is inside of root root is at the top of everything so if you look around carefully you'll see the home directory sitting in the root directory and if you go in there CD home and you type in LS you will see your username okay and then CD sake then you type in LS and now you're back over here this and this match so remember this will take you to the root of your Linux operating system and inside of root you've got all kinds of fancy things that you don't want to worry about right now so let's do a quick recap let's go to the music folder CD music so I'm now in the music's folder or the directory I'm going to be using the the word folder and directory interchangeably interchangeably and they're gonna be mean B meaning the same exact thing okay so in here let's type in PWD so that means prank working directory and it tells you that you are in fact focused on the music folder again if you go over here here's the music folder if you go to home here's the music folder okay it's empty let's type in LS to see if it is really empty it is in fact empty so next I'm going to show you how to copy or move a file so let's go back CD space dot takes us back and do an LS and let's say I want to go into the Documents folder so I type in CD Documents and then type in LS and here what I have is I have a test file so this is one of the files what I want to do what I want to do is I want to copy this file and I'm gonna use the CP command for that that stands for a copy I'm gonna copy this test file and I'm going to paste it into the same folder with a different name so test copy and I'm going to press Enter okay just to give you make you understand exactly what happens so you use the copy command you pick the file that you're trying to copy and then you give it a brand new name to create the copy within the same folder okay so if I type in LS now you have the first file test and then you've got test copy now how do I remove this file you use the RM command okay so the RM command is used
to delete file in your current folder.
so if you type in RM test copy
and you type in LS as you can see test
copy is gone and we only have test
left over now what if I want to copy
test file and I want to paste it
into the Downloads folder how do you
do that okay what you got to do is you
have type in CP and you take the test
file and then you have to tell the
computer where do you want to put the
copy of the test file so remember if
you go up here we're working under
home / sake okay so what you want to
do is you want to do slash home slash
sake slash downloads and you press
ENTER and type in LS we still have the
test file right here now
let's go back CD doc type in LS
and let's navigate to the Downloads
folder and if I type in LS here now
we've got the file test sitting here
which we copied over from the
Documents folder so let's go ahead
and remove this file from the
Downloads folder so our M is the
remove command RM test and remember
because we are focused in two downloads
when we do RM test its gonna dump
it's gonna delete the test file only
from the Downloads folder because
that is where we are focused on press
ENTER type in list one more time LS
and now there's nothing there left
so let's go back let's just type in
PWD and we're back in a home sake okay
next the next style let's talk about
making a new folder and deleting the
new folder so let me launch this right
here and I'm gonna minimize I'm gonna
make this a little thinner here okay
so you can still see what's going on
one second alright so that's better
so let's go to my arm My Documents over
here and let's go to CD documents
oops Dawkins okay so now we're in the
Documents folder and all we have in
here is the test file which you can
see right here let's make a new
folder so how you make a new folder
you use the command called MK dir
press ENTER and it's gonna say some
kind of error because we were missing
an operand okay so we were missing the
new directory we used the command what
we did not specify the name of the
directory so you type in MK dere dir
and then you type in test folder I'm
gonna use capital letters here okay
and as you can see over here a test
folder was created instantly and I
can actually go into that test folder
if I wanted to LS and there's nothing
in there.
so let's go back CD dot dot
and let's delete the test folder so
how do you delete that what you do is
you using the commune's the command
rmdir so this one is make directory
this one is remove directory type in
test folder and I'm not gonna press
ENTER take a look over here and let's
come back here and press ENTER and that
directory disappears now if the directory had something inside it we cannot delete the directory that has stuff in it using our m dir okay so let's uh MK dir make another directory in the Documents folder and say test ok so it popped up right here and let's go
inside here and let's just create a new document ok new doc now if I try to delete this using rmdir test folder let's go back here ok so now the test folder has a file in it it is the new doc okay if I try to delete this it's gonna say failed to remove test directory is not empty so how do you delete this you have to actually use
theRM command which is a remove
command for files but what you do is
you have to set a new option you have
to say - R and then you have to type
in test ok so watch this there's still
a file in here but it's just gonna
disappear okay so everything in test
has been removed so this is how you
delete folders that have existing files
inside of them you use the RM command
you put a space you put a minus R and
then you put a space and then you put
the name of the directory right
underneath and right next to minus R okay so here it's got a really messy here so let's use the clear command to clear the screen real quick and I'm going to talk about a couple other commands and we're gonna end the tutorial here all right so the final command I want to go over is called a man command okay MA and now this stands for manual
manuals okay like like tutorials so when
you don't know what you're doing and you
want to find out more about any command that you're using you can type in man space and let's just say the LS command which is the list command and you press ENTER it's gonna give you a whole lot of information regarding the LS command so you're gonna get the name of the command
which is LS it says list directory contents okay you get a quick setup synopsis you get a description of what the command exactly does and all that stuff and once you're done reading this whole thing you just type key Q to quit okay so let's do one more man and let's do the CP command which is the copy command press ENTER and it says here it copies files and directories okay and you have a description here and you can read through this whole thing and you can keep pressing enter to get more information so press ENTER to continue okay to go all the way but when you're done you can press Q and it just quits the manual so that's how you can get information on any command that you want in Linux alright and thanks for watching this video now there are going to be more Linux tutorials coming soon so go ahead and subscribe to my channel for more videos to come give me a thumbs up if you liked this video and you can also follow me on Facebook Google+ and Twitter okay so you have all these options all links to my social media websites and my actual website are
found in the description below alright thanks for watching again and I'll see you the next time

windows 10 part 2

      
    

                              windows 10


  if you want to along the far left of the Start menu is where you’ll find File Explorer which is where you can access Files and folders on your computer Settings and below that is power where You can restart shutdown or put your Computer to sleep more on settings later Just like iOS and Android Microsoft has its own App Store for Windows you can find it in the list by Selecting a letter jump to M and finding Microsoft Store in the list if you plan To go here often I’d recommend pinning it to your taskbar Currently it’s in my taskbar just to the Right of file explorer so I’ll open it Up on their home page you’ll find Featured items along the top you can Select categories that include apps Games movies and TV and books if you Know what you’re looking for you can do A search I’ll do a search for Kody and There it is to install any app select Get to the far right if you select the Menu icon You have the options to view downloads And updates store settings your library Along with other account information now Let’s go take a look at the various Settings for Windows 10 if you’ve used Older versions of Windows you should be Familiar with the control panel which You can still access by typing control Panel into the search bar or you could Say hey Cortana control panel alright Which control panel do you want to open Control panel or settings control panel Alright starting control panel here you Can still access many of the settings For your computer since Microsoft is Slowly phasing out the control panel Will focus on the primary Settings app For Windows 10 you could ask Cortana to Open settings or you could just go to  The Start menu and select the Settings Icon with settings open I’ll move quickly through each of these Categories highlighting options that Might be of interest to you we’ll go Through these in order starting with System displays where you can rearrange And change settings for your monitors You can change the order of your Displays by selecting the number and Dragging it to the left or to the right A cool feature introduced last year is Nightlight which can reduce the blue Light on your screens at night which Studies claim can make you sleep better In notifications and actions you can add Or remove quick actions which show up When you select notifications that I Showed you earlier if you scroll down This page you can turn on or off which Apps are allowed to send you Notifications power and sleep is where You can set your power settings for more Options select additional power settings And select a plan that works best for You here you can see your storage Storage sense is something that I leave On to automatically free up space tablet Mode is useful for those of you that Have a Microsoft Surface or similar Device that can be used as a tablet and In multitasking There is no need to turn any of these Off now for devices most of these are Self-explanatory bluetooth and other Devices you can see what’s connected to Your system or add devices printers and Scanners will show you what’s connected To your system here’s where you can Change your mouse settings in typing I Would suggest leaving these turned on Especially if you’re a horrible sspelle And in USB make sure this one is checked So you can get notified if there are and Issues connecting to USB devices if you Select phone you can link an Android or iPhone to be able to work continuously between your PC and phone with compatible apps for some of you this is a feature that might be useful in network and Internet you can see your network status set up Wi-Fi and other options for those of you that thought dial-up was dead it’s not there are still many areas in the United States and around the world that don’t have broadband service yet personalization is where you can make changes to the overall look of Windows 10 I’ll spend a little bit more time in this category you can set the background to be a slideshow just a single picture or a solid color you can browse your computer for other pictures that you would prefer to have as your background you can set how often the picture gets cchange anywhere from one minute to one day if you put a checkmark here you can automatically have the system pick an accent color based on your background currently the accent color on my system is blue but you can change it to any of the colors listed and if you scroll down this page in previous videos many have asked how I got this dark background for the settings menu when you first launch Windows 10 light is the default for me It’s a little too bright so I prefer the Dark when you’re on your lockscreen

                    The default pictures are going to be From Microsoft if you want to change That you can choose your own picture or Use your slideshow I’ll just stick with The windows spotlight here themes is a Great place to personalize Windows 10 I currently have several themes you can Get additional themes in the Windows Store and there are a lot to choose from If you need more screen space and you Want to get rid of the taskbar when I Use often is automatically hide the Taskbar in desktop mode when you head Into the apps category you will see a Listing of all the software and apps on Your system This is a good place to uninstall Software that you no longer need so just Find a program that you want to get rid Of and then select uninstall default Apps as the name implies is a good place To set defaults for email maps music Player and so on and so forth when you First install Windows 10 Microsoft edge Will be your default web browser on your System this is a shocker it even say Here it’s recommended for Windows 10 to Change any of the defaults just to Choose another app that’s listed will Skip over accounts which is where you Can add accounts to your system time and Language is an area where you shouldn’t Have to message the settings too much For some of you the text-to-speech Settings may be useful to change the Voice to one of the three listed and to Change the speed some youtubers use Text-to-speech to narrate their videos In gaming if you don’t plan to record or Broadcast your gameplay you may want to Consider turning the game bar off many Players that have installed games from The Microsoft Store have experienced a Multitude of game crashes on low and High powered systems many have noticed By turning the game bar off that crashes To their desktop have reduced Substantially the ease of access Settings is where you want to go if you Have difficulty hearing seeing or Working with your keyboard or Mouse just Select one of the categories on the left That you think will help you out and Adjust the settings we already discussed Cortana earlier so let’s go into the Privacy settings in a recent video I Discussed a couple settings that might Be useful for you to increase your Privacy first in general you can turn Off advertising ID then go down the left Pane to speech inking and type And you can turn off speech services and Typing suggestions if you turn the Second one off you won’t be able to Speak to Cortana the last settings Category is update and security the only Settings in this category that have had To change are in Windows Update it says I have an update that’s available the Status is a waiting restart which will Happen outside of active hours you don’t Want your system to restart if you’re Actively using your computer so select Change active hours and select the hours You do not want windows to automatically Restart your computer if you want to Specify a time for Windows to restart to Finish installing updates go to restart Options make sure this toggled on and Select a time and day below that you’ll See show more notifications it’s Typically a good idea to leave this Turned on just in case you forgot that You had scheduled it’ll time to restart Your computer the notification will Allow you to delay the restart if needed And with that this closes out the Windows settings portion of this video If you need further assistance with Using Windows 10 I’ve created a playlist That I will link to in the description With 17 other videos including useful Keyboard shortcuts tips to speed up Performance along with others that Hopefully will help you out thanks for Watching give this video a thumbs up if It was useful for you it’s difficult to Cover everything in this type of video So let me know in the comments if you Have any other tips that you think might Be beneficial for others to know and if You haven’t done so already click on the Subscribe button and bail notification Icon for more Windows 10 tips and other Tech related stuff from tech gumbo

windows 10 part 1

          

                                     windows 10     


  The Windows 10 operating system has been Out for more than a couple years nowI still get questions on how to perform Certain tasks and which settings to use Within the operating system whether you’re new to Windows 10 Having just upgraded from an older Operating system recently purchased a new computer with Windows 1 pre installed or like many others that Have become frustrated with Mac OS Operating system from Apple and have Finally made the switch to a Windows Computer in this beginner’s guide I will Go over the basic settings and give you A tour of Windows 10 to get you started With using the operating system coming Up next on tech combo if you’re familiar With the other tutorials on this channel I try to present everything in simple Terms this video will follow that same Format I’ll go over the basic layout Show you how to perform certain tasks And later in this video we’ll dig deepInto the settings menu for Windows 10 if You’re a power user you may not learn a Whole lot here since this is a Beginner’s guide this video is intended For brand new users to the operating System to learn the absolute basics Let’s dive right in when you log into Windows 10 you will see your desktop Your layout may vary slightly from mine You’ll have your main window with the Bar covering the bottom of the page that Is where you will find the Start menu on
              The far left the Cortana bar task view The task bar the status bar Notifications and arrow peek to the far Right more on those later let’s first Look at the primary window you’ll have Your wallpaper in the background I’ve Run a multiple monitors setup so I Typically don’t keep shortcuts or Anything else on my primary screen I’ll Drag them over right now from another Monitor most software that you install Will put a shortcut on your desktop if You happen to install software that Doesn’t I’ll now show you a quick way to Add a shortcut to your desktop let’s Pretend that the Google Chrome browser Did not add a shortcut to your desktop To add it go to the Cortana search bar Here at the bottom type Google Chrome Into the search bar do not use the Microphone function For this right-click on Google Chrome And select open file location’ find the Icon right-click hover over sendto then Click on desktop create shortcut now the Shortcut for chrome is on the desktop Let’s close out this window you can move The icons wherever you want them also in The main window if you right-click you Have several choices in view you can Change the size of the icons you can Sort them by name size item type date Modified if you select next desktop Background you can change your wallpaper For new you have several options Including adding a new folder to your Desktop if you select display settings Here you can make changes to your Display I’ll go into more detail on These later on and if you select Personalize it will open up the Personalization options I’ll go into More detail on these later on in the Video as well now let’s take a look at The bottom bar starting with Cortana Which is similar to Google assistant and Siri and can also be used to search your Computer you could either click on the Microphone or you could use the word hae Followed by the word Cortana to ask your Questions here’s an example hey Cortana   
                  What’s the weather in New York City Right now there’s a winter storm warning In effect until 1:00 a.m. tomorrow right Now It’s cloudy and 27 in New York hey Cortana tell me a joke what is the Difference between a well dressed man on A unicycle and a poorly dressed man on a Bicycle attire those are a couple of Quick examples on how to use for tana I’ve made a couple videos last year on How to use the assistant and another Video with questions you can ask Cortana I’ll click into the search bar along the Left side if you go down to the Settings Icon to be able to use your microphone To get the assistant to respond to the Key You’ll want to turn this on to the right Of Cortana is task view where you can Add virtual desktop layouts so for Example if you work from home you could Have desktop one be your personal Workspace and desktop two eeverythin Associated with your work and you can Add new desktops by selecting the plus Sign let’s go back to desktop one to theRight of task view is the taskbar where You can pin some of your favorite Programs pinning from your desktop is Easy I’ll go up here and grab upper Aniion and drag it down here to the Taskbar and that will pin it to the Taskbar to remove programs just Right-click on the icon and select unpin From taskbar and you can move these Icons around if you want you so I’ll Drag the baldy here to the right and Adobe Creative Cloud to the left to the Far right is the status bar you can Choose what is visible and what is not If you select the up arrow it will show You those programs that are not visible Here in the status bar to move one of Those items to the status bar you can Click and drag it down and to remove an Item from the status bar you can just Click and drag it up here is where You’ll find your notifications so if you Click on notifications they’ll show up Right here if you have any and you’ll Have a quick access menu to your network All settings Bluetooth VPN and others And to the far right you can barely see It it’s just a sliver is arrow peak just To the right of notifications I’ll open Up a program to show you what it does When I select arrow peek it’ll show the Desktop and selecting it again will show Open windows one of the most Controversial aspects of Windows 10 is The Start menu if you left-click you get The new Start menu if you right click You get a menu that looks like the Classic start menu found on Windows 7 or Older here you can quickly access many Features and settings for the purposes Of this video both Focus on the primary Start menu by Left-clicking on the windows icon along The left you’ll see programs listed in Alphabetical order if you select any of The letters I’ll select a you can Quickly jump around the list I’ll select S I’ll hover my mouse over a program Right-clicking you have the option to Pin to the Start menu which will make The program appear to the right where it Says more you have the option to pin to Your taskbar rate and review and share And you can also uninstall the program From here to the right our tiles of your Applications I’ll admit that I still Don’t like and have not used this Feature much since it was introduced in Windows 8 I just showed you how to pin Tiles to your Start menu if you Right-click a tile you have several Options most notably being able to Resize the tiles currently I have Netflix set on medium and I’ll make this Wider you can even move the tiles around        

Mac OS X ios

Mac os X ios
 

         
                                   

  So let's begin with macOS tutorial. This is the default screen of macOS which is known as desktop and on the top we get a horizontal bar which is known as menu bar. At the bottom of the desktop we can find dock on which App shortcuts are present. So first let's check the features of the menu bar. So first we have Apple logo in which the first option is About this Mac from About this Mac we can check the system's hardware configuration and find the macOS version as you can see here. Below About this Mac we can find System Preferences. System Preferences is basically a control panel from where we can modify the software and hardware settings. Further in this video we will check the System Preferences in detail. After this we can find Appstore by clicking on which opens Appstore. Below it we have Recent Items which shows the recently opened items. After this we have Force Quit. By using Force Quit we can check which apps are open and if an app hangs we can forcefully quit it from here. Below Force Quit we can find   Sleep
          Restart
          Shutdown
          Lockscreen
          Log Out Options.
                    Besides the Apple logo we can find ......... Finder 
Finder is macOS's default file manager which can be used to browse the macOS. We will discuss about Finder in detail later.
                After Finder the next important option is GO. By using GO we can directly go to any location. like we can to Downloads similarly we can click on GO and go to applications where we can find all the installed apps.
                 Now let's check the icons on the right hand side of the menu bar. Over here you can find WiFi icon from where you can connect or disconnect the WiFi network. After this we have Battery icon by clicking on which you can show or hide the battery percentage. 
                After Battery icon we have Date and Time which can be set to Digital or Analog. After this you can find the Logged In User's name besides which we have Spotlight Search. which is macOS's lightning fast search engine from where you can search anything within this macOS. Finally we can find the Notifcation Bar from where you can check the notifcations. So these were the default menu bar details
but if you see closely there are some icons missing. like Volume and Bluetooth icons So in order to bring these icons to the menu bar we will go to System Preferences and click on Sound. 
              And here on the bottom we will click on show volume in menu bar due to which we can find the Volume icon on the menu bar Similarly we can go to Bluetooth and tick on show Bluetooth in menu bar due to which now we find the Bluetooth icon on the menu bar. And in order to rearrange or remove these icons
you need to press and hold the command button on your keyboard and by dragging left or right with the pointer you can rearrange these icons or by dragging the icons down you can remove them as well as you can see in the video. 
             Now let's check the Dock on the dock we can find the shortcuts for the installed applications and at the very end we have Trash Bin. The actual location of all the shortcuts is the Application folder here you can see that the Safari app is installed and if you remove it from the dock it will not be deleted from the Applications folder because there are only shortcuts on the dock and we can drag Safari back to dock For dock settings we will go to system preferences and select dock. Here we can set the dock size which you can see in real time and by turning on magnification the dock icons will magnify when we scroll the pointer through them. And the magnification size can be set manually and from here we can set the dock's positioning to the left or bottom or to the right. And by ticking on this option we can auto hide the dock as well and the shortcuts which you don't want on the dock that can be removed by clicking on secondary and then selecting the Remove from Dock option or you can directly remove them by drag and drop.
             Let's remove some shortcuts from here Now we will check important system preferences settings Firstly we have General In Appearance we can set between light and dark theme and by using this option we can auto hide the menu bar After this we have desktop and screen saver settings from where you can set the desktop wallpaper and screen saver After this we have dock settings which we have already checked in detail.
           After this in important settings, we can find Internet Accounts Here accounts such as iCloud, Google, Yahoo and other accounts can be added which will get synchronized by the macOS's mail app Users & Groups From here we can add and delete user accounts and also change the related settings and by using Bluetooth settings, Bluetooth can be turned On or Off and also pair Bluetooth devices.
        In Sound settings, you can see the output and input devices and also modify the related settings. And most importantly let's check the Trackpad settings In trackpad by default, the secondary click is by two fingers but we will set it to bottom right click just like Windows laptop and on the right, you can also watch the preview video And below this, we will also enable tap to click. Here we can also set the trackpad's tracking speed From the Scroll & Zoom tab, we can set the scroll direction and check the zoom in and zoom out gestures with video preview on right.
          Similarly, you can also see the smart zoom and rotate gestures. In More Gestures, you can see swipe between pages, swipe between Fullscreen apps, Notification Center, Launchpad, etc all these trackpad gestures can be learned. Apple's trackpad is one of the best trackpads which makes the overall user experience better. In Display, you can change the display resolution and brightness and other display-related changes can be done. In Energy-saving settings, if you have a dual graphics MacBook you can turn On or Off the Automatic graphics switching and energy saver related settings for the battery and power adapter can be set separately. Lastly from the Date and Time, you can set the date and time-related settings. Now let's check the macOS's Finder which is macOS's default file manager Firstly we will go to Finder Preferences and tick on Hard-disk due to which we will get the built-in hard-disks icon on the desktop. We can click on finder icon on the dock to open the Finder window or double click on the hard disk icon to open the Finder window On the left-hand side of the Finder window, we can find sidebar in which we can find the Favourites and Tags option. On the Finder window's top left corner three colored circles from which using the Green colored circle we can make the window full-screened and in order to exit the full screen we need to click the Green circle again. Using the Yellow circle minimizes the window which goes to the dock from where we can bring it back and by using the Red circle we can close the window but most of the applications don't close by the Red circle. Let's check an example we will open Safari app you can see that in the menu bar Safari's menu is merged and even after clicking the Red circle Safari app is still open in the background as you can see in the menu bar. To quit this, we can go to Safari and select the Quit Safari option which will completely close the Safari app. So this is how you can close the application. 
                     We can resize the Finder window from any corner easily as you can see We can easily browse any files from the Finder window on the left, we can find a sidebar where under Favourites Airdrop, Recents, Desktop, etc their location shortcuts can be found. You can also easily customize these by going into Finder preferences We need to select sidebar and from here you can add or remove shortcuts from the favorites as you can see in the video. By double-clicking on the harddisk we can directly come to the hard disks root location where we can find four folders At the very first, we have Applications folder in which all our installed applications are present. Second folder is Library in which macOS related important files are present. Third folder is System in which again macOS related important folders are present. And at last we can find the users folder in which we have the actual user's, home folders and under home folders there are actual predefinded folders like desktop, documents, downloads, etc In fact, all the shortcuts on the sidebar are from these locations Now we will learn how to create a new folder and how to rename, cut, copy and paste. In order to create a new folder you need to click secondary and select new folder you can rename it on the spot or do secondary click and select the rename option as you can see in the video. We will rename it as Demo We can drag and drop this folder to rearrange it or you can do a secondary click and select the sort by name option to rearrange it alphabetically. In order to delete this folder you can secondary and select the move to bin option to delete it which will dump it in the trash bin. From the trash bin you can permanently empty it or you can do the secondary click and select the put back option to recover it as well. which will put it back to it's original location from where it was deleted. In order to copy and paste you need to select the copy option from the secondary click then go to the desired location and from the secondary option click on paste item which will paste it. So this was a very easy step but in macOS, to cut, paste or move is a bit different
                      if you notice, you will see that after secondary click you won't find the cut option anywhere but don't worry it's a bit of a tricky step you need to select the copy option and then go to the location you want to move it to and do the secondary click and simultaneously you need to press the option button on the keyboard due to which we can find the move option which will move the copied item here. 

Android


  
     
 
       
                                                             Android 
  what is Android operating system present it by zero to pro training com in this video we will talk about what is Android operating system it is an operating system based on the Linux kernel it is designed primarily for touchscreen mobile devices touchscreen devices include smartphones and tablet computers it is initially developed by and joined incorporated Admiral incorporated was financially backed by Google the company was later bought by Google in 2005 Android operating system was unveiled in 2007 the Open Handset Alliance was founded at the same time Open Handset Alliance is a consortiumof hardware software and telecommunication companies these companies are devoted to advancing open standards for mobile devices the first publicly available smartphone running Android who was HTC dream it was released on October 22nd 2008 the user interface of Android is based on direct manipulation using touch inputs example of touchin pits are swiping tapping pinching and reverse pinching internal hardware are used by some applications to respond to additional user actions examples of hardware are accelerometers gyroscopes and proximity sensors example of youth erections are adjusting the screen from portrait to landscape depending on how the device is oriented Android allows users to customize their home screens with shortcuts to applications and widgets widgets allow users to display live content directly on the home screen examples are emails and weather information applications can further send notifications to the user to inform them of relevant information example if notifications are new emails and text messages Android source code is released by Google under the Apache License this permissive licensing allows the software to be freely modified and distributed by device manufacturers wireless carriers and enthusiast developers most Android devices are shipped with a combination of open source and proprietary software as of July 2013 Android has the largest number of applications or apps available for download in Google Play Store the Play Store has over 1 million apps published and over 50 billion downloads a developer survey conducted in 2013
found that Android is the most used platform among developers it is used by 71% of the mobile developers population Android is popular with technology companies which require a ready-made low-cost and customizable operating system for high tech devices despite being primarily designed for phones and tablets it also has been used in televisions games console's digital cameras and other electronics Androids open nature has encouraged a
large community of developers and enthusiasts to use the open source code
as a foundation for community drive projects as of May 2012 Android became the most popular mobile OS it is the largest installed base it is a market leader in most countries including the United States in the third
quarter of 2013 Android share of the global smartphone shipment market led by
Samsung products was 81.3% the highest ever in most markets Android powered phones are the most popular comprising more than half of the overall smartphone sales the operating system success has made it a target for patent litigation as part of the so-called smartphone wars between technology companies as of September 2013 1 billion Android devices have been activated

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