PHP Examples

PHP 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.

<?php
function Palindrome($MyNum) {
  $revNum = 0;
  $Num = $MyNum;

  while($Num > 0) {
    $digit = $Num % 10;
    $revNum = $revNum * 10 + $digit;
    $Num = (int)($Num / 10);
  }

  if ($MyNum == $revNum){
    echo $MyNum." is a Palindrome number.\n";
  } else {
    echo $MyNum." is not a Palindrome number.\n";
  }
}

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.