CI codeigniter框架中的site_url()与base_url()的区别

//在"application/config/config.php"文件中设置：
$config['base_url']='http://localhost/CodeIgniter/'

site_url("student/index/str/1");
base_url("student/index/str/1");

base_url:http://localhost/Codeigniter/student/index/str/1

site_url:http://localhost/Codeigniter/index.php/student/index/str/1