C program to reverse a number

Comprehensive Collection of C Programming Examples

In this example, you will learn to reverse the number entered by the user.

To understand this example, you should know the followingC programmingTopic:

• C programming operators

• C while and do ... while loops

Reverse integer

#include <stdio.h>
int main() {
　　　　int n, rev = 0, remainder;
　　　　printf("Enter an integer: ");
　　　　scanf("%d", &n);
　　　　while (n != 0) {
　　　　　　　　remainder = n %%　10;
　　　　　　　　rev = rev　*　10　+　remainder;
　　　　　　　　n　/=　10;
　　　　}
　　　　printf("Reverse number = %d", rev);
　　　　return 0;
}

Output result

Enter an integer:　2345
reverse number =}}　5432

This program takes an integer input from the user. Then it uses　 while loop until it is false (0) for n != 0.

in each iteration of the loop, the remainder of n when calculated is divided by10and decrease the value n by10times.

Inside the loop, use the following formula to calculate the reciprocal:

rev = rev*10　+　remainder;

Comprehensive Collection of C Programming Examples