C++ basic tutorials: Variables

Hi, This is the 2nd part of the C++ Tutorial. Just Click here to check the 1st part 

One of the important think of C++ is variables. Variables are simply placeholders. It represents storage location in your computer memory. The variable concept of mathematics and C++ are almost the same. They just hold some terms or figures in your computer memory and use that terms or figures afterwards.

In C++, in order to make variables you need to write the type of that variable (data types). The summery of fundamental data types are as follows: 

Name	Description	Size*	Range*
char	Character or small integer.	1byte	signed: -128 to 127 unsigned: 0 to 255
short int (short)	Short Integer.	2bytes	signed: -32768 to 32767 unsigned: 0 to 65535
int	Integer.	4bytes	signed: -2147483648 to 2147483647 unsigned: 0 to 4294967295
long int (long)	Long integer.	4bytes	signed: -2147483648 to 2147483647 unsigned: 0 to 4294967295
bool	Boolean value. It can take one of two values: true or false.	1byte	true or false
float	Floating point number.	4bytes	+/- 3.4e +/- 38 (~7 digits)
double	Double precision floating point number.	8bytes	+/- 1.7e +/- 308 (~15 digits)
long double	Long double precision floating point number.	8bytes	+/- 1.7e +/- 308 (~15 digits)
wchar_t	Wide character.	2 or 4 bytes	1 wide character

Source: http://www.cplusplus.com/doc/tutorial/variables/

Syntax of variable:

#include <iostream>

using namespace std;

int main()

{

     int x = 15;

     cout << x << endl;

     return 0;

}

Here, int is the data type and x is the variable. Write  cout << x << endl; for printing on the screen.

Then press Ctrl + F5 for debugging.

Summation program:

#include <iostream>

using namespace std;

int main()

{

     int x = 15;

     int y = 26;

     int z ;

     z = x + y;

     cout <<x << " + "<<y <<" = "<< z;

     return 0 ;

}

Output:

N.B: int data type is only for non-decimal numbers. You can also use other data types for example, you can use double instead of int for decimal figures.

User input:

A user can also input something with his keyboard, which will be processed by the compiler. To take inputs from the user, simply type cin>> between the {------} curly brackets.

 For example, in summation program, to take inputs from the user just write this syntax.

#include <iostream>

using namespace std;

int main()

{

     int x;

     int y;

     int z;

     cin >> x;

     cin >> y;

     z = x + y;

     cout <<x << " + "<<y <<" = "<< z;

     return 0 ;

}

And run that program and the output will be…….

 

If you have Microsoft Visual C++ or any other compiler installed in your computer, you can just check the above programs.

variable(.cpp)

sum_variable(.cpp)

sum_user_input(.cpp)

To read C++ Tutorial part 3 Click here


Thank you for reading ;)