Increment and decrement operators in C

Increment Operators are used to increase 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.

There are two special unary operator in C/C++, called increment(++) and decrement(--) operators that changes the value of variable by a unit.

Syntax:

Increment Operator : ++

Decrement Operator : --

Example:

int i=1;

i++;

then i=2

int j=5;

j--;

then j=4

 Note :

i++ is same as i=i+1;

j-- is same as j=j-1;

Types of Increment Operator :

(a).Post Increment: varName ++

In post increment statement, first use the value of variable and then increment it.

For example;

int i=1;

int x= i++ + i;

Output:

x=2

(b).Pre Increment : ++varName

In pre increment statement, first increment and then use its value after completion of equation.

For example;

int i=1;

int x= ++i + i;

Output:

x=4

Types of Decrement Operator :

(a).Post Decrement : varName--

In post decrement statement, first use the value of variable and then decrement it.

For example;

int i=5;

int x= i-- + i;

Output:

x=10

(b).Pre Decrement : --varName

In post decrement statement, first decrement and then use its value after completion of equation.

For example;

int i=5;

int x= --i + i;

Output:

x=8

Complete Example:

#include<stdio.h>

int main(){

          int i=1,j=1,k=5,l=5,x1,x2,y1,y2;

//        printf("X1=%d\n",++(i+j));

          x1=i++ + i;

          printf("I=%d,X1=%d\n",i,x1);

          x2=++j + j;

          printf("J=%d,X2=%d\n",j,x2);

         

          y1=k-- + k;

          printf("K=%d,Y1=%d\n",k,y1);

          y2=--l + l;

          printf("L=%d,Y2=%d\n",l,y2);

         

          return 0;

}

Output:

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