To develop a simple calculator class in the context of PHP is more fun with __call()
magic method.
class Calculator { public function __call($method, $args) { if (isset($this->$method)) { $func = $this->$method; return call_user_func_array($func, $args); } } } $calculator = new Calculator(); $calculator->add = function ( $a1, $a2 ) { echo $a1 + $a2; }; $calculator->subs = function( $a1, $a2 ) { echo $a1 - $a2; }; $calculator->multi = function( $a1, $a2 ) { echo $a1 * $a2; }; $calculator->div = function( $a1, $a2 ) { echo $a1 / $a2; };