This operator is used to add one value in the Variable. It is a unary operator that is denoted by double plus sign (++). The double plus sign can be used before or after the (only single) variable name. In both cases, the value of the variable incremented by 1 but their functions are different in expressions and other operations. There are two types of increment operator:
- Postfix Increment Operator
- Prefix Increment Operator
What is Postfix Increment Operator?
When increment operator (++) is written after the variable name, it is known as postfix increment operator. In this case, first the value of variable is used in operation and then variable is incremented by one.For example, to add 1 to variable "x", the statement is:
x++;
Example Program of Postfix
To clear the concept about it, a set of statements is as follows:
#include
main()
{
int a = 15, b;
b = a++;
coutreturn 0;
}
Output of Program
Value of a = 16 , Value of b = 15Working of Postfix Increment Operator
The above statements are executed by the following rules:- First assignment statement a = 15; is executed and value 15 is assigned to variable "a".
- Then statement b = a++; is executed by the following two steps:
- Value of "a" is assigned to "b". (Such as 15 assigned to variable b.
- 1 is added to "a" (Such as value of "a" becomes 16).
Note: The statement b = a++; is equivalent to following two statement:
b = a;
or
a = a + 1;
What is Prefix Increment Operator?
If the increment operator (++) is written before the variable name then it's know as prefix increment operator. In this case, first the variable incremented by one and then value of the variable is used in the operation. Such as, to add 1 to variable "y", the statement is:
++y;
Example Program of Prefix Increment Operator
To understand it batter, look at the following example program:
#include
main()
{
int y = 20, z;
z = ++y;
cout
return 0;
}
Output of Program
Value of y = 21 , Value of z = 21Working of Prefix Increment Operator
The above program is executed by the following rules:- First assignment statement y = 20; is executed and value 20 is assigned to variable "y".
- Then statement z = ++y; is executed by the following two steps:
- First value of "y" is incremented by 1 (Such as, it becomes 21)
- Then value of "y" is assigned to variable "z" (as value of "y" became 21, the value of z is also 21).