<?php?$p="";//定義圓周率的兩種取值define("PI1",3.14);define("PI2",3.142);//定義值的精度$height = "高";//根據(jù)精度返回常量名，將常量變成了一個可變的常量if($height == "中"){? ? $p = "PI1";}else if($height == "低"){ $p = "PI2";}else if($height =="高"){? ? $p = 5;}$r=1;$area = constant($p)*$r*$r;echo $area;?>
constant()函數(shù)不能直接調(diào)用常數(shù)么？
慕粉1131507708
2017-01-24 11:38:34
