php返回HTTP状态码

面试时很多人问我这个，记录一下   200是ok,  404表示页面未找到.
HTTP协议状态码,调用函数时候只需要将$num赋予一个下表中的已知值就直接会返回状态了。
<?PHP 
/** 
* HTTP Protocol defined status codes
* HTTP协议状态码,调用函数时候只需要将$num赋予一个下表中的已知值就直接会返回状态了。
* @param int $num
*/ 
function https($num) { 
$http = array ( 
100 => "HTTP/1.1 100 Continue", 
101 => "HTTP/1.1 101 Switching Protocols", 
200 => "HTTP/1.1 200 OK", 
201 => "HTTP/1.1 201 Created", 
202 => "HTTP/1.1 202 Accepted", 
203 => "HTTP/1.1 203 Non-Authoritative Information", 
204 => "HTTP/1.1 204 No Content", 
205 => "HTTP/1.1 205 Reset Content", 
206 => "HTTP/1.1 206 Partial Content", 
300 => "HTTP/1.1 300 Multiple Choices", 
301 => "HTTP/1.1 301 Moved Permanently", 
302 => "HTTP/1.1 302 Found", 
303 => "HTTP/1.1 303 See Other", 
304 => "HTTP/1.1 304 Not Modified", 
305 => "HTTP/1.1 305 Use Proxy", 
307 => "HTTP/1.1 307 Temporary Redirect", 
400 => "HTTP/1.1 400 Bad Request", 
401 => "HTTP/1.1 401 Unauthorized", 
402 => "HTTP/1.1 402 Payment Required", 
403 => "HTTP/1.1 403 Forbidden", 
404 => "HTTP/1.1 404 Not Found", 
405 => "HTTP/1.1 405 Method Not Allowed", 
406 => "HTTP/1.1 406 Not Acceptable", 
407 => "HTTP/1.1 407 Proxy Authentication Required", 
408 => "HTTP/1.1 408 Request Time-out", 
409 => "HTTP/1.1 409 Conflict", 
410 => "HTTP/1.1 410 Gone", 
411 => "HTTP/1.1 411 Length Required", 
412 => "HTTP/1.1 412 Precondition Failed", 
413 => "HTTP/1.1 413 Request Entity Too Large", 
414 => "HTTP/1.1 414 Request-URI Too Large", 
415 => "HTTP/1.1 415 Unsupported Media Type", 
416 => "HTTP/1.1 416 Requested range not satisfiable", 
417 => "HTTP/1.1 417 Expectation Failed", 
500 => "HTTP/1.1 500 Internal Server Error", 
501 => "HTTP/1.1 501 Not Implemented", 
502 => "HTTP/1.1 502 Bad Gateway", 
503 => "HTTP/1.1 503 Service Unavailable", 
504 => "HTTP/1.1 504 Gateway Time-out"  
); 
header($http[$num]); 
} 
?>
@header(’HTTP/1.0 404 Not Found’);