<?php

echo "以下演示变量的传值方式赋值：";
echo "<br>";
echo "定义a=我是a，b=a 。";
echo "<br>";
$a = "我是a";
$b = $a;
echo "a的值：".$a;
echo "<br>";
echo "b的值：".$b;
echo "<br>";
echo "修改 b的值=变成c 。";
echo "<br>";
$b = "变成c";
echo "a的值是：".$a;
echo "<br>";
echo "b的值是：".$b;
echo "<br>";
echo "传值方式赋值，改变变量的值不会影响其他变量的值。";
echo "<br>";


echo "<br>";
echo "以下演示变量的引用方式赋值：";
echo "<br>";
echo "定义 a=我是大，b=&a 。";
echo "<br>";
$a = "我是大";
$b = &$a;
echo "a的值：$a";
echo "<br>";
echo "b的值：$b";
echo "<br>";
echo "修改 b=我是小";
echo "<br>";
$b = "我是小";
echo "a的值是：$a";
echo "<br>";
echo "b的值是：$b";
echo "<br>";
echo "引用方式赋值，改变变量的值，同时会改变引用的变量的值。请注意此方式。";