PHP program to find palindrome

In this tutorial I’m going to show you how to find a word or a sentence is a Palindrome in PHP.

You may find scripts online but most of them are difficult to understand and almost all of them used loops to find it, but this php script I have written is very simple and not used any loops.

Let’s see the script:

<html>
<body>
	<h3>Find Palindrome or Not in PHP</h3>
	<form action="" method="post">
		<label>Enter a word or a sentence<label>
		<input type="text" name="string" />
		<input type="submit value="Submit" />
	</form>
</body>
</html>

<?php 


	
if($_POST){

	$string = $_POST['string'];
	
	//remove all spaces
	$string = str_replace(' ', '', $string);
	
	//remove special characters
	$string = preg_replace('/[^A-Za-z0-9\-]/', '', $string);
	
	//change case to lower
	$string = strtolower($string);
	
	//reverse the string 
	$reverse = strrev($string);
	
	if($string == $reverse){
		echo "<p>It is Palindrome</p>";
	}else{
		echo "</p>Not Palindrome</p>";
	}
	
}

?>

Read the comments in the script to understand what is happening.

Few palindrome words and sentences to check:

1. madam
2. civic
3. Madam, I’m Adam
4. A man, a plan, a canal: Panama.
5. No lemon, no melon.

The basic concept is reversing the entered string and comparing the string with the original string using  (==) comparison operator. if both the original string and reversed string matched, then it is a Palindrome.

See the demo in here: