call_user_func_array call instance

When you import a certain class file and want to call this class file, call_user_func_array function. Here are two examples according to different parameters:

<?php    
$func = function($arg1, $arg2) {    
return $arg1 * $arg2;    
};    
var_dump(call_user_func_array($func, array(2, 4))); /* As of PHP 5.0 */    
?>

The output will be:

int(8) [1]‍

<?    
Class ClassA    
{    
    
function bc($b, $c) {    
     $bc = $b + $c;    
echo $bc;    
}    
}    
call_user_func_array(array(&#39;ClassA&#39;,&#39;bc&#39;), array("111", "222"));    
    
//显示 333    
?>

First parameter: class name, function. Second function: Pass in parameters

Maybe you will ask: Under what circumstances is the function call_user_func_array used? When calling a certain function, just call it directly with new. Isn’t it unnecessary?

The difference between call_user_func_array and new class names is that if the first parameter of all_user_func_array is array('class name','method name'), the system will automatically create an object for the class to execute the method directly, but it will not be executed. The __construct constructor method is equivalent to calling the static method class name::function name (parameter), and when new class name is used, the constructor will be executed first.