You must have read printf and scanf statements in C language. One prints the output on screen and the other scans what you entered.

The standard C++ library includes the header file iostream, where the standard input and output stream objects are declared.

In CPP , cout prints on the screen whereas cin scans, similar to printf,scanf in c language.

In the above program integer type variable v is scanned and 5 is added to it and the result is printed on the screen.

For e.g if you add 5 as value in the program above it will output as:

Enter a value: 5

The value you entered is  5 and adding five to it makes it 10  .