require_once('../../lib/some_class.php');

 define('ROOT' , pathinfo(__FILE__, PATHINFO_DIRNAME));require_once(ROOT . '../../lib/some_class.php');

require_once('lib/Database.php');
require_once('lib/Mail.php');
require_once('helpers/utitlity_functions.php');

function load_class($class_name)
{$path = ROOT . '/lib/' . $class_name . '.php');require_once( $path );
}
load_class('Database');
load_class('Mail');

function load_class($class_name)
{$path = ROOT . '/lib/' . $class_name . '.php');if(file_exists($path)){include( $path );}
}

/**Method to execute a command in the terminalUses :1. system2. passthru3. exec4. shell_exec*/function terminal($command){if(function_exists('system')){ob_start();system($command , $return_var);$output = ob_get_contents();ob_end_clean();}elseif(function_exists('passthru')){ob_start();passthru($command , $return_var);$output = ob_get_contents();ob_end_clean();}elseif(function_exists('exec')){exec($command , $output , $return_var);$output = implode("\n" , $output);}elseif(function_exists('shell_exec')){$output = shell_exec($command) ;}else{$output = 'Command execution not possible on this system';$return_var = 1;}return array('output' => $output , 'status' => $return_var);}terminal('ls');

<?phpclass super_class{function super_function(){}}//No closing tag

function print_header()
{echo "<div id='header'>Site Log and Login links</div>";
}
function print_footer()
{echo "<div id='footer'>Site was made by me</div>";
}
print_header();
for($i = 0 ; $i < 100; $i++)
{echo "I is : $i ';
}
print_footer();

function print_header()
{$o = "<div id='header'>Site Log and Login links</div>";return $o;
}
function print_footer()
{$o = "<div id='footer'>Site was made by me</div>";return $o;
}
echo print_header();
for($i = 0 ; $i < 100; $i++)
{echo "I is : $i ';
}
echo print_footer();

//Attempt to connect to database$c = mysqli_connect($this->host , $this->username, $this->password);//Check connection validityif (!$c)
{die ("Could not connect to the database host: ". mysqli_connect_error());
}//Set the character set of the connection
if(!mysqli_set_charset ( $c , 'UTF8' ))
{die('mysqli_set_charset() failed');
}//一旦连接数据库, 最好设置连接的 characterset. 你的应用如果要支持多语言, 这么做是必须的

$contents = "All the content";
$dir = '/var/www/project';
$file_path = $dir . "/content.txt";
if(is_writable($dir))
{file_put_contents($file_path , $contents);
}
else
{die("Directory $dir is not writable, or does not exist. Please check");
}

//Delay for some time
function delay()
{$sync_delay = get_option('sync_delay');echo "Delaying for $sync_delay seconds...";sleep($sync_delay);echo "Done ";
}用静态变量取代:
//Delay for some time
function delay()
{static $sync_delay = null;if($sync_delay == null){$sync_delay = get_option('sync_delay');}echo "Delaying for $sync_delay seconds...";sleep($sync_delay);echo "Done ";
}

$_SESSION['username'] = $username;
$username = $_SESSION['username'];

//从现在开始, 使用应用相关的key和一个包装函数:define('APP_ID' , 'abc_corp_ecommerce');//Function to get a session variable
function session_get($key)
{$k = APP_ID . '.' . $key;if(isset($_SESSION[$k])){return $_SESSION[$k];}return false;
}//Function set the session variable
function session_set($key , $value)
{$k = APP_ID . '.' . $key;$_SESSION[$k] = $value;return true;
}

>>使用echo取代print
>>使用str_replace取代preg_replace, 除非你绝对需要
>>不要使用 short tag
>>简单字符串用单引号取代双引号
>>head重定向后记得使用exit
>>不要在循环中调用函数
>>isset比strlen快
>>始中如一的格式化代码
>>不要删除循环或者if-else的括号
>>不要尝试省略一些语法来缩短代码. 而是让你的逻辑简短
>>使用有高亮语法显示的文本编辑器. 高亮语法能让你减少错误
>>使用 php filter
>>验证数据强制类型检查
>>如果需要,使用profiler如xdebug
>>由始至终使用单一数据库连接
>>避免直接写SQL, 抽象之
>>在head中使用base标签
>>永远不要將 error_reporting 设为 0　　eg:error_reporting(~E_WARNING & ~E_NOTICE & ~E_STRICT);

$arr = array_map('trim' , $arr);

>>使用 defines/constants
>>使用函数获取值
>>使用类并通过$this访问