If a number, which when read in both forward and backward way is same, then such a number is called a palindrome number.

Program:

#include <stdio.h>

int main() {

int n, n1, rev = 0, rem;

printf("Enter any number: \n");

scanf("%d", &n);

n1 = n;

/* logic */

while (n > 0){

rem = n % 10;

rev = rev * 10 + rem;

n = n / 10;

}

if (n1 == rev){

printf("Given number is a palindromic number");

}

else{

printf("Given number is not a palindromic number");

}

return 0;

}

Output:

Enter any number: 121

Given number is a palindrome

Explanation with an example:

Consider a number n=121, reverse=0, remainder;

number=121

now the while loop is executed /* the condition (n>0) is satisfied */

/* calculate remainder */

remainder of 121 divided by 10=(121%10)=1;

now reverse=(reverse*10)+remainder

=(0*10)+1 /* we have initialized reverse=0 */

=1

number=number/10

=121/10

=12

now the number is 12, greater than 0. The above process is repeated for number=12.

remainder=12%10=2;

reverse=(1*10)+2=12;

number=12/10=1;

now the number is 1, greater than 0. The above process is repeated for number=1.

remainder=1%10=1;

reverse=(12*10)+1=121;

number=1/10 /* the condition n>0 is not satisfied,control leaves the while loop */

Program stops here. The given number=121 equals the reverse of the number. Thus the given number is a palindrome number.