Check if Binary Representation is Palindrome or not in C

🔷 C Program: Check if Binary Representation is Palindrome

#include <stdio.h>
#include <string.h>

void inttobinary(int num, char binary[])
{
    int index = 0;
    while (num > 0)
    {
        binary[index++] = (num % 2) + '0';
        num /= 2;
    }
    binary[index] = '\0';

    // Reverse the binary string
    for (int i = 0; i < index / 2; i++)
    {
        char temp = binary[i];
        binary[i] = binary[index - 1 - i];
        binary[index - 1 - i] = temp;
    }
}

int pal(char str[])
{
    int start = 0;
    int end = strlen(str) - 1;

    while (start < end)
    {
        if (str[start] != str[end])
        {
            return 0;
        }
        start++;
        end--;
    }
    return 1;
}

int main()
{
    int num;
    char binary[50];

    printf("Enter the number: ");
    scanf("%d", &num);

    if (num == 0)
    {
        printf("The binary representation of 0 is palindrome.\n");
        return 0;
    }

    inttobinary(num, binary);

    if (pal(binary))
    {
        printf("The binary representation of %d is a palindrome.\n", num);
    }
    else
    {
        printf("The binary representation of %d is not a palindrome.\n", num);
    }

    return 0;
}
  

📘 Explanation:

This program checks whether the **binary representation** of a given decimal number is a **palindrome**.

🔹 The function inttobinary() converts a given integer to its binary equivalent using division by 2. Digits are stored in reverse order and later reversed to get the correct binary format.

🔹 The function pal() checks if a given string is a palindrome by comparing characters from both ends until the middle.

🔹 In main(), the number is taken from the user. If it is 0, it's directly reported as a binary palindrome.
🔹 Otherwise, it converts the number to binary and checks if the result is a palindrome, printing the appropriate message.

🔍 Sample Output:

Enter the number: 9
The binary representation of 9 is a palindrome.

Enter the number: 10
The binary representation of 10 is not a palindrome.
    

🏷️ Keywords:

binary palindrome, binary conversion in C, C palindrome check, number to binary in C, C programs for beginners, string reversal, strcmp, strlen, strcpy