25.C Program to Reverse a Number

C Program to Reverse a Number

Example to reverse an integer entered by the user. This problem is solved using while loop in this example.

To understand this example, you should have the knowledge of following C programming topics:

• C Programming Operators
• C programming while and do...while Loop

Example: Reverse an Integer

#include <stdio.h>
int main()
{
    int n, reversedNumber = 0, remainder;

    printf("Enter an integer: ");
    scanf("%d", &n);

    while(n != 0)
    {
        remainder = n%10;
        reversedNumber = reversedNumber*10 + remainder;
        n /= 10;
    }

    printf("Reversed Number = %d", reversedNumber);

    return 0;
}

Output

Enter an integer: 2345
Reversed Number = 5432

This program takes an integer input from the user. Then the while loop is used until n != 0 is false.

In each iteration of while loop, the remainder when n is divided by 10 is calculated and the value of n is reduced by times. 

Check out these related examples:

• C Program to Count Number of Digits in an Integer
• C Program to Compute Quotient and Remainder
• C Program to Print an Integer (Entered by the User)