文件名：expression.php
<?php
//表达式示例
$y=($x=10+5);
echo " <b>表达式示例： </b> <br>\$y=(\$x=10+5) <br>";
echo "\$x=$x,\$y=$y <br> <br>";
//算术运算符
echo " <b>算术运算符： </b> <br>";
echo "5+3*6=".(string)(5+3*6)." <br>";
echo "40-84/4=".(string)(40-84/4)." <br>";
echo "32-27%4=".(string)(32-27%4)." <br>";
echo " <br>";
//递增/递减运算符
echo " <b>递增/递减运算符： </b> <br>";
$a=10;
echo "\$a=$a <br>";
echo "10-++\$a=".(string)(10-++$a).",\$a=$a <br>";
$a=10;
echo "\$a=$a <br>";
echo "10-\$a++=".(string)(10-$a++).",\$a=$a <br>";
$a=10;
echo "\$a=$a <br>";
echo "10+--\$a=".(string)(10+--$a).",\$a=$a <br>";
$a=10;
echo "\$a=$a <br>";
echo "10+\$a--=".(string)(10+$a--).",\$a=$a <br>";
echo " <br>";
//比较运算符
echo " <b>比较运算符： </b> <br>";
echo "1==
<!--购买数量-->
<div class='buyinfo'>
<table width='auto'>
<tr>
<td><span>购买数量：</sp ......
