实现任意两个数的加减乘除

function computer($num1,$num2,$opt){

switch($opt){

case "+":

$reslut = $num1+$num2;

break;

case "-":

$reslut = $num1-$num2;

break;

case "*":

$reslut = $num1*$num2;

break;

case "/":

$reslut =  $num2==0? '错误'：$num1/$num2;

break;

default:

$reslut="错误";

}

return $reslut;

}

echo computer(10,5,*);