<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>蝴蝶教程（cainiaoya.com）</title>
</head>
<body>
<code>
$a = 5;
$b = 10;
$c = $a+$b;
echo $c;
</code>
</body>
</html>
