Check Whether a Number is a Palindrome
This program determines if a given integer is a palindrome. A palindrome retains the same sequence of digits when reversed (e.g., 121 or 5445). We do this by reversing the digits and comparing the result to the original number.
#include <stdio.h>
int main() {
int n, orig, rev = 0, rem;
printf("Enter an integer: ");
scanf("%d", &n);
orig = n; // Save the original number
while (n != 0) {
rem = n % 10; // Extract last digit
rev = rev * 10 + rem; // Append to reversed number
n /= 10; // Remove last digit
}
if (orig == rev) {
printf("%d is a palindrome.\n", orig);
} else {
printf("%d is not a palindrome.\n", orig);
}
return 0;
}Enter an integer: 1221
1221 is a palindrome.
After storing the input in orig, the program reverses the digits in the same way as the reverse-number example. Finally, it compares the reversed value to the original. If they match, the number reads the same forwards and backwards and is therefore a palindrome.
