PHP源码解析（一）

常用PHP运算类型介绍与应用
1、算术运算
例：
    5 * 6 - 12
    2*(28+1)
    
注：算术运算遵循数学运算规则 
从左到右，先算乘除后算加减，遇到括号先算括号内
2、赋值运算
例：
$a=1;
$a+=2;
$a*=3;
   ......

PHP条件语句的介绍与应用
1、if 条件语句
if(expr)
    echo TRUE
else
    echo FALSE
if(expr) {
    echo TRUE
}else{
    echo FALSE
}
f(expr) {
    echo&n ......

在php中计算时间差有时候是件麻烦的事!不过只要你掌握了日期时间函数的用法那这些也就变的简单了:  
一个简单的例子就是计算借书的天数,这需要php根据每天的日期进行计算,下面就来谈谈实现这种日期计算的几种方法:
(1) 如果有数据库就很容易了!若是MSSQL可以使用触发器!用专门计算日期差的函数datediff()便可 ......

Perl is a language often associated with text processing and CGI. PHP is
a language often associated with dynamic Web pages. Both are very popular
with Web developers. Often, each of these languages is used at the expense of
the other. Hard-core Perl developers would love to develop everyth ......

ob_start();
echo "<pre>";
print_r($content);
echo "</pre>";
$a=ob_get_contents();
$filename = $_SERVER['DOCUMENT_ROOT']."/log-".date("Y-m-d").".txt";
$file = fopen($filename, "a");
$tipmsg = "\r\n******Final File: "
//.end(explode('/',$_SERVER['PHP_SELF']))
.$_SERV ......