C Program - Check whether a Number is Palindrome or not

A number is known as a Palindrome number if the reverse of the number is same as the number. For example, 121 is a palindrome number, but 123 is not a palindrome number.

Example: Check Palindrome Number

In the example below, the number called MyNum is checked for palindrome number. The MyNum is first stored in a variable called Num. A while loop is used on this variable to perform following operations:

• last digit of the Num variable is estimated using Num % 10 and stored in digit variable.
• reverse number is built using revNum * 10 + digit.
• last digit is removed from Num variable using Num / 10.

Finally, MyNum is compared with revNum to check whether the number is palindrome or not.

#include <stdio.h>

static void Palindrome(int MyNum) {
  int revNum = 0;
  int Num = MyNum;
  while(Num > 0) {
    int digit = Num % 10;
    revNum = revNum * 10 + digit;
    Num = Num / 10;
  }
  if (MyNum == revNum) {
    printf("%i is a Palindrome number.\n", MyNum);
  }
  else {
    printf("%i is not a Palindrome number.\n", MyNum);
  }
}

int main() {
  Palindrome(12521);
  Palindrome(9779);
  Palindrome(1000);
}

The above code will give the following output:

12521 is a Palindrome number.
9779 is a Palindrome number.
1000 is not a Palindrome number.