Palindrome Check Program in C

This program checks if a given number is a palindrome. A palindrome is a number that remains the same when its digits are reversed. For example, 121 and 12321 are palindromes.

Program Structure and Explanation

The program follows these steps:

1. Prompt the user to enter a number.
2. Reverse the digits of the entered number.
3. Compare the reversed number with the original number.
4. Print a message indicating whether the number is a palindrome.

Documentation

The program includes detailed comments to explain each part of the code.

Code

#include <stdio.h>

// Function to check if a number is a palindrome
int isPalindrome(int number);

int main() {
    int number;
    
    // Prompt the user to enter a number
    printf("Enter a number: ");
    scanf("%d", &number);
    
    // Check if the number is a palindrome
    if (isPalindrome(number)) {
        printf("%d is a palindrome.\n", number);
    } else {
        printf("%d is not a palindrome.\n", number);
    }
    
    return 0;
}

/**
 * Function to check if a number is a palindrome
 * @param number The number to check
 * @return 1 if the number is a palindrome, 0 otherwise
 */
int isPalindrome(int number) {
    int originalNumber = number; // Store the original number
    int reversedNumber = 0;      // Initialize the reversed number
    int remainder;
    
    // Reverse the digits of the number
    while (number != 0) {
        remainder = number % 10;
        reversedNumber = reversedNumber * 10 + remainder;
        number /= 10;
    }
    
    // Check if the reversed number is equal to the original number
    if (originalNumber == reversedNumber) {
        return 1;
    } else {
        return 0;
    }
}

Explanation of the Code

• #include <stdio.h>: Includes the standard input-output library.
• int isPalindrome(int number);: Declares the function prototype for checking if a number is a palindrome.
• int main(): The main function where the program execution begins.
• int number;: Declares a variable to store the user input.
• printf("Enter a number: ");: Prompts the user to enter a number.
• scanf("%d", &number);: Reads the input number from the user.
• if (isPalindrome(number)): Calls the isPalindrome function and checks the result.
• printf("%d is a palindrome.\n", number);: Prints a message if the number is a palindrome.
• printf("%d is not a palindrome.\n", number);: Prints a message if the number is not a palindrome.
• int isPalindrome(int number): Defines the function to check if a number is a palindrome.
• int originalNumber = number;: Stores the original number for later comparison.
• int reversedNumber = 0;: Initializes the reversed number.
• int remainder;: Declares a variable to store the remainder of division.
• while (number != 0): Loops until the number becomes 0.
• remainder = number % 10;: Gets the last digit of the number.
• reversedNumber = reversedNumber * 10 + remainder;: Builds the reversed number.
• number /= 10;: Removes the last digit from the number.
• if (originalNumber == reversedNumber): Checks if the reversed number is equal to the original number.
• return 1;: Returns 1 if the number is a palindrome.
• return 0;: Returns 0 if the number is not a palindrome.