Add two numbers using bitwise operators in php

Php program for Add two numbers using bitwise operators. Here problem description and other solutions.

<?php
// Php program for
// Add two numbers using of bitwise operators
class NumberAddition
{
	// Add two numbers
	public	function addition($a, $b)
	{
		// Display given numbers
		echo "\n [($a) + ($b)] ";
		// Auxiliary variable which are store the carry bit result
		$carry = 0;
		// Executing loop, until b value is not zero
		while ($b != 0)
		{
			// Get carry bits of a & b
			$carry = $a & $b;
			// Sum of bits of a ^ b
			$a = $a ^ $b;
			// Shift the carry bit by one bit in left side
			$b = $carry << 1;
		}
		// Display add result
		echo " : $a";
	}
	public static function main()
	{
		$task = new NumberAddition();
		// Test Case
		$task->addition(8, -2);
		$task->addition(5, 3);
		$task->addition(-3, -5);
	}
}
NumberAddition::main();

Output

 [(8) + (-2)]  : 6
 [(5) + (3)]  : 8
 [(-3) + (-5)]  : -8