C Exercises: Display the number in reverse order

Last update on July 31 2025 05:46:30 (UTC/GMT +8 hours)

37. Reverse a Given Number

Write a program in C to display a given number in reverse order.

The program should prompt the user to input a number, then process the number to reverse its digits. Finally, the program will display the reversed number to the user.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h> // Include the standard input/output header file.

void main(){
    int num, r, sum = 0, t; // Declare variables for the original number, remainder, reversed number, and temporary variable.

    printf("Input a number: "); // Prompt the user to input a number.
    scanf("%d", &num); // Read the input from the user.

    for(t = num; num != 0; num = num / 10){ // Loop to reverse the digits of the number.
         r = num % 10; // Extract the last digit (remainder when divided by 10).
         sum = sum * 10 + r; // Build the reversed number by adding the extracted digit.
    }

    printf("The number in reverse order is : %d \n", sum); // Print the reversed number.
}

Output:

Input a number: 12345                                                                                         
The number in reverse order is : 54321

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to reverse a number using recursion instead of loops.
Write a C program to reverse a number without using division or modulus operators (convert to string method).
Write a C program to reverse the digits of a number and then check if the original and reversed numbers are identical (palindrome check).
Write a C program to reverse a number and then output the difference between the original number and its reverse.

Go to:

PREV : Pattern with 1 as First and Last Number.
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