1# 主要讲了四个外接文件的函数，分别是include,include_once,require,require_once。

include and include_once :if there is something wrong,they will not throw an error, they will just be ingored.

requre and require_once :if there is something wrong ,thye will throw a fatal error, and blocking the page .

2#养成好的习惯，变量和函数用{}括起来。

<?php

　　function hello($name) {

　　return "hello {$name}!";

}

?>

PHP with MySQL essential training-10.5including and require files