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HomeBackend DevelopmentPHP TutorialPHP利用func_get_args和func_num_args函数实现函数重载实例_PHP

本文实例讲述了PHP利用func_get_args和func_num_args函数实现函数重载的方法。分享给大家供大家参考。具体方法分析如下:

学习php的朋友都知道php本身是没有函数重载这一说的,更没说像java,c那样使用方法,但如果我们深入了解一下会发现可以在php中使用func_get_args()和func_num_args()函数实现函数重载,下面来举两个函数重载例子.这两个函数实现函数的重载.

1、默认参数,如果一个函数里面,这不是必须参数,而添加相应的默认值,就可以完成相应的功能,代码如下:

代码如下:

function overloadFun($param1, $param2 = '1',$param3 = true) 

 // do something  
}


利用函数func_get_args()和call_user_func_array(),PHP代码如下:

代码如下:

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($arg1, $arg2) {    
echo $arg1, ' ', $arg2;    
}    
   
rewrite('PHP'); //调用func1    
rewrite('PHP','China'); //调用func2


2、使用默认值,从而根据输入,得到自己想要的结果,代码如下:

代码如下:

function test($name="小李",$age="23"){   
echo $name."  ".$age;   
}   
test();   
echo "
";   
test("a");   
echo "
";   
test("a","b");


3、利用__call($name, $arg) 函数进行处理,代码如下:

代码如下:

class OverLoad{ 
function __call($name, $args) 

  if($name=='overloadFun') 
  { 
   switch(count($args)) 
   { 
    case 0: $this->overloadFun0();break; 
    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($var1) 

  echo $var1; 

function overloadFun2($var1,$var2) 

   
  echo $var1+$var2; 
   } 
}   
$test=new OverLoad(); 
$test->overloadFun()."
".  
$test->overloadFun(1)."
".  
$test->overloadFun(1,2)."
"; 
?>


有了这样的方法之后我们就可以利用它们来实现简单函数重载了,但有一点要注明的是php 作为一种弱类型语言,本身不能像强类型如java,c++那样,直接的实现重载,至少现在不可以以后版本会不会有我们不知道.

希望本文所述对大家的PHP程序设计有所帮助。

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