<?php
class calculator
{
public $a;
public $b;
public $c;
public $d;
public $y;
public $z;
function plus($a, $b, $c, $d)
{
$y = $a + $b;
$z = $c + $d;
echo $z;
}
function minus($a, $b)
{
$y = $a + $b;
$z = $c + $d;
echo $z;
}
}
$obj = new calculator();
$obj->plus(1, 2, 3, 4);
$obj->minus(9, 8, 7, 6);
