PHP include 引入变量文件

index.php

<?php
	include "connect.php";

	echo "a:".($a);
	echo "<br>";
	echo "b:".($b);
	echo "<br>";
	echo "c:"."$c";
	echo "<br>";
	echo "d:"."$d";
	echo "<br>";
	echo "e:"."$e";

connect.php

<?php
    $a="1";
    $b="2";
    $c=$a+$b;
    $d=$c+"5";
    $e="10"/"3";