As the title says, the source code is as follows <!DOCTYPE html><html><head> Simple calculator</head><body> <?php $num1 = $_GET["num1"]; $num2 = $_GET["num

There is no problem after reading the code. The final output is <?php if(isset($_GET["sub"])) echo $sun; ?>

I saw a calculator written in PHP on the Internet, but it cannot achieve calculation output. Please help!

如题，源码如下

<!DOCTYPE html>

<html>

<head>

简易计算器

</head>

<body>

<?php

$num1 = $_GET["num1"];

$num2 = $_GET["num2"];

if($_GET["ysf"]==" ")

$sun = $num1 $num2;

if($_GET["ysf"]=="-")

$sun = $num1-$num2;

if($_GET["ysf"]=="*")

$sun = $num1*$num2;

if($_GET["ysf"]=="/")

$sun = $num1/$num2;

</select>

</form>

<?php

if(isset($_GET["sub"]))

echo $sun;

</body>

</html>

季风2408 days ago1494