C Exercises: Check whether a number is a palindrome or not

Last update on March 18 2025 13:34:36 (UTC/GMT +8 hours)

38. Palindrome Number Check

Write a C program to check whether a number is a palindrome or not.

This program should prompt the user to input a number, then check if the number reads the same forwards and backwards. If the number is a palindrome, the program will display a message confirming this; otherwise, it will indicate that the number is not a palindrome.

Visual Presentation:

Check whether a number is a palindrome or not

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.
    }

    if(t == sum) // Check if the original number and the reversed number are equal.
         printf("%d is a palindrome number.\n", t); // Print a message if it is a palindrome.
    else
         printf("%d is not a palindrome number.\n", t); // Print a message if it is not a palindrome.
}

Output:

Input a number: 121                                                                                           
121 is a palindrome number.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to check if a number is a palindrome using recursion for digit reversal.
Write a C program to determine if a number is a palindrome by comparing digits from both ends.
Write a C program to verify a number's palindrome property without converting it to a string.
Write a C program to check if a number is a palindrome and then compute the sum of its digits.

C Programming Code Editor:

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