Front-end PHP entry -014-parameters Reference

We have learned the references to variables, so let's review the Knowledge:

  
 

   
  

  
 <?php
   
  

  

   
  

  
 $a = 10;
   
  

  

   
  

  
 $b = &$a;
   
  

  

   
  

  
 $a = 100;
   
  

  

   
  

  
 echo $a.‘---------‘.$b;
   
  

  
 ?>
  
 

Instead, the parameter reference of the function points to the same position as the formal parameter and the argument. If the parameter changes in the function body, the value of the argument also changes. Let's go through the experiment to see:

  
 

   
  

  
 <?php
   
  

  

   
  

  
 $foo = 100;
   
  

  

   
  

  
 //注意：在$n前面加上了&符
   
  

  
 function demo(&$n){
   
  

  

   
  

  
 $n = 10;
   
  

  

   
  

  
 return $n + $n;
   
  

  

   
  

  
 }
   
  

  

   
  

  
 echo demo($foo).‘<br />‘;
   
  

  

   
  

  
 //你会发生$foo的值变为了10
   
  

  
 echo $foo;
   
  

  

   
  

  
?>
  
 

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From for notes (Wiz)

Front-end PHP entry -014-parameters Reference