Increment and Decrement Operator in C

Increment and Decrement Operator in C

Increment Operators are used to increased the value of the variable by one and Decrement Operators are used to decrease the value of the variable by one in C programs.

Both increment and decrement operator are used on a single operand or variable, so it is called as a unary operator. Unary operators are having higher priority than the other operators it means unary operators are executed before other operators.

 ++  // increment operator
 --   // decrement operator

Note: Increment and decrement operators are can not apply on constant.

x= 4++;  // gives error, because 4 is constant

Type of Increment Operator

• pre-increment
• post-increment

pre-increment (++ variable)

In pre-increment first increment the value of variable and then used inside the expression (initialize into another variable).

++ variable;

#include<stdio.h>
#include<conio.h>

void main()
{
int x,i;
i=10;
x=++i;
printf("x: %d",x);
printf("i: %d",i);
getch();
}

x: 11
i: 11

In above program first increase the value of i and then used value of i into expression.

post-increment (variable ++)

In post-increment first value of variable is used in the expression (initialize into another variable) and then increment the value of variable.

variable ++;

#include<stdio.h>
#include<conio.h>

void main()
{
int x,i;
i=10;
x=i++;
printf("x: %d",x);
printf("i: %d",i);
getch();
}

x: 10
i: 11

In above program first used the value of i into expression then increase value of i by 1.

Type of Decrement Operator

• pre-decrement
• post-decrement

Pre-decrement (-- variable)

In pre-decrement first decrement the value of variable and then used inside the expression (initialize into another variable).

-- variable;

#include<stdio.h>
#include<conio.h>

void main()
{
int x,i;
i=10;
x=--i;
printf("x: %d",x);
printf("i: %d",i);
getch();
}

x: 9
i: 9

In above program first decrease the value of i and then value of i used in expression.

post-decrement (variable --)

In Post-decrement first value of variable is used in the expression (initialize into another variable) and then decrement the value of variable.

variable --;

#include<stdio.h>
#include<conio.h>

void main()
{
int x,i;
i=10;
x=i--;
printf("x: %d",x);
printf("i: %d",i);
getch();
}

x: 10
i: 9

In above program first used the value of x in expression then decrease value of i by 1.

Example of increment and decrement operator

#include<stdio.h>
#include<conio.h>

void main()
{
int x,a,b,c;
a = 2;
b = 4;
c = 5;
x = a-- + b++ - ++c;
printf("x: %d",x);
getch();
}

x: 0