C Program: Reversing a number using a Do-While loop

C Do-While Loop: Exercise-12 with Solution

Write a C program to reverse a given number using a do-while loop.

Sample Solution:

C Code:

#include <stdio.h>

int main() {
    int num, reversedNum = 0, remainder;

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

    // Store the original number in a separate variable
    int originalNum = num;

    // Reverse the number using a do-while loop
    do {
        // Extract the last digit
        remainder = num % 10;

        // Build the reversed number by appending the extracted digit
        reversedNum = reversedNum * 10 + remainder;

        // Remove the last digit from the original number
        num = num / 10;

    } while (num != 0);

    // Print the original and reversed numbers
    printf("Original Number: %d\n", originalNum);
    printf("Reversed Number: %d\n", reversedNum);

    return 0;  // Indicate successful program execution
}

Sample Output:

Input a number: 235235
Original Number: 235235
Reversed Number: 532532

Input a number: -1234
Original Number: -1234
Reversed Number: -4321

Explanation:

Here are key parts of the above code step by step:

• int num, reversedNum = 0, remainder;: Declares variables to store the original number (num), reversed number ('reversedNum'), and remainder.
• printf("Input a number: ");, scanf("%d", &num);: Prompts the user to enter a number and reads it.
• int originalNum = num;: Stores the original number in a separate variable.
• do { ... } while (num != 0);: Uses a do-while loop to reverse the number.
• remainder = num % 10;: Extracts the last digit of the number.
• reversedNum = reversedNum * 10 + remainder;: Builds the reversed number by appending the extracted digit.
• num = num / 10;: Removes the last digit from the original number.
• printf("Original Number: %d\n", originalNum);, printf("Reversed Number: %d\n", reversedNum);: Prints the original and reversed numbers.
• return 0;: Indicates successful program execution.

Flowchart:

C Programming Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Calculating compound interest with User input Loop.