C Program to Reverse a Given Number using While loop, Do-while, For loop

C program to reverse a given number using a while loop, do-while, and for loop.

In this article, you will learn how to make the reverse of a given number by using programming loops like while, do-while, and for.

Example

You should know about the following topics in C programming to understand this program:

• While loop in C
• Do-while loop in C
• For loop in C

1 - Reverse a Given Number using While loop

// C Program to Reverse a Given Number using While loop
#include <stdio.h>

// It's the main function of the program
int main()
{
    int num, rev = 0, rem, original;

    // Step-1 Take an input from the User
    printf("INPUT: ");
    scanf("%d", &num);

    // Step-2 Store the input value into the `original` variable
    original = num;

    // Step-3 Iterate over the input number using the loop
    while (num != 0)
    {
        rem = num % 10;
        rev = rev * 10 + rem;
        num /= 10;
    }

    // Step-4 Check if the reminder of original divided by 10 is equal to Zero
    if (original % 10 == 0)
    {
        printf("\nOutput Reversed Number: %d", rev);

        while (original % 10 == 0)
        {
            printf("0");
            original /= 10;
        }
    }

    // Step-5 If a reminder of the original is not equal to Zero
    else
    {
        printf("\nOutput Reversed Number: %d", rev);
    }

    return 0;
}

Run

Output

2 - Reverse a Given Number using Do-while loop

// C Program to Reverse a Given Number using Do-while loop
#include <stdio.h>

// It's the main function of the program
int main()
{
    int num, rev = 0, rem, original;

    // Step-1 Take an input from the User
    printf("INPUT: ");
    scanf("%d", &num);

    // Step-2 Store the input value into the `original` variable
    original = num;

    // Step-3 Iterate over the input number using the loop
    do
    {
        rem = num % 10;
        rev = rev * 10 + rem;
        num /= 10;
    } while (num != 0);

    // Step-4 Check if the reminder of original divided by 10 is equal to Zero
    if (original % 10 == 0)
    {
        printf("\nOutput Reversed Number: %d", rev);

        do
        {
            printf("0");
            original /= 10;
        } while (original % 10 == 0);
    }

    // Step-5 If a reminder of the original is not equal to Zero
    else
    {
        printf("\nOutput Reversed Number: %d", rev);
    }

    return 0;
}

Run

3 - Reverse a Given Number using For loop

// C Program to Reverse a Given Number using For loop
#include <stdio.h>

// It's the main function of the program
int main()
{
    int num, rev = 0, rem, original;

    // Step-1 Take an input from the User
    printf("INPUT: ");
    scanf("%d", &num);

    // Step-2 Store the input value into the `original` variable
    original = num;

    // Step-3 Iterate over the input number using the loop
    for (int n = num; n != 0; n /= 10)
    {
        rem = n % 10;
        rev = rev * 10 + rem;
    }

    // Step-4 Check if the reminder of original divided by 10 is equal to Zero
    if (original % 10 == 0)
    {
        printf("\nOutput Reversed Number: %d", rev);

        for (int o = original; o % 10 == 0; o /= 10)
            printf("0");
    }

    // Step-5 If a reminder of the original is not equal to Zero
    else
    {
        printf("\nOutput Reversed Number: %d", rev);
    }

    return 0;
}

Run

Output