php foundation knowledge！

php foundation knowledge！

 

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1 <?php  2 $p = "PII";  3 define("XPI",3.1415926);  4 define("PI",3.14,true);  5 define($p,3.14,false);  6 echo XPI;  7 echo "<br />xPI 默认false ：对大小写敏感！<br />";  8 echo xPI;//默认false 对大小写敏感  9 echo "<br />"; 10 echo PI; 11 echo "<br />Pi 设置true ：对大小写不敏感！<br />"; 12 echo Pi; 13 echo "<br />"; 14 echo PII; 15 echo "<br />"; 16 echo Pii; 17 echo "<br />"; 18 ?>

　　

 

 

<?php
$p = "PII";
define("XPI",3.1415926);
define("PI",3.14,true);
define($p,3.14,false);
echo XPI;
echo "<br />xPI 默认false ：对大小写敏感！<br />";
echo xPI;//默认false 对大小写敏感
echo "<br />";
echo PI;
echo "<br />Pi 设置true ：对大小写不敏感！<br />";
echo Pi;
echo "<br />";
echo PII;
echo "<br />";
echo Pii;
echo "<br />";
?>