PHP uses Func_get_args and Func_num_args functions to implement the function overloading method

PHP's friends know that PHP itself is not a function overload of the said, not to mention the use of methods like java,c, but if we dig deeper we will find that you can use the Func_get_args () and Func_num_args () functions in PHP to implement function overloading, Here are two examples of function overloading. These two functions implement overloading of functions.

1, the default parameters, if a function inside, this is not required parameters, and add the corresponding default value, you can complete the corresponding function, the code is as follows:

The code is as follows:

function Overloadfun ($param 1, $param 2 = ' 1 ', $param 3 = True)  {   //do something   }

Using the Functions Func_get_args () and Func_num_args (), the PHP code is as follows:

The code is as follows:

function rewrite () {     $args = Func_get_args ();     if (Func_num_args () = = 1) {     func1 ($args [0]),     } else if (Func_num_args () = = 2) {     func2 ($args [0], $args [1]);     }     }         function Func1 ($arg) {     echo $arg;     }         function Func2 ($arg 1, $arg 2) {     echo $arg 1, ', $arg 2;     }         Rewrite (' PHP '); Call func1     rewrite (' PHP ', ' China ');//Call Func2

2, use the default value, so according to the input, get the result you want, the code is as follows:

The code is as follows:

function Test ($name = "Xiao Li", $age = "All") {    echo $name.  $age;    }    Test ();    echo "<br/>";    Test ("a");    echo "<br/>";    Test ("A", "B");

3, the use of __call ($name, $arg) function for processing, the code is as follows:

The code is as follows:

<?php  class overload{  function __call ($name, $args)  {    if ($name = = ' Overloadfun ')    {     Switch (count ($args))     {case      0: $this->overloadfun0 ();      Case 1: $this->overloadfun1 ($args [0]); break;      Case 2: $this->overloadfun2 ($args [0], $args [1]); break;      Default://do something break        ;       }}} function OverloadFun0 ()  {    echo 0;  } function OverloadFun1 ($var 1)  {    echo $var 1;  } function overloadFun2 ($var 1, $var 2)  {        echo $var 1+ $var 2;     }    $test =new overload ();  $test->overloadfun (). " <br/> ".   $test->overloadfun (1). " <br/> ".   $test->overloadfun. " <br/> ";  ? >

With this method we can use them to implement simple function overloading, but one thing to note is that PHP as a weakly typed language, itself can not be like a strong type, such as java,c++, the direct implementation of overloading, at least now can not later version will not have we do not know.