A detailed explanation of the PHP sort usage

How many sort functions in PHP do you write this yourself?! Then think about it, I was wrong, programming is not rote mechanical movement, but also a collection of multiple thinking; The aim of the algorithm is to expand the purpose of his thinking.

So I tried to write it.

  
   
   

   
    
    
 
     

       <?php Tutorial 
      
$array = Array (10,5,36,86,2,56,9,15,8,4,3,41); 
      
$num = count ($array); 
      
for ($i = 0; $i < $num-1; $i + +) { 
      
for ($j = $i +1; $j < $num; $j + +) { 
      
if ($array [$j]> $array [$i]) {///here Exchange the value of the array 
      
$temp = $array [$i]; 
      
$array [$i] = $array [$j]; 
      
$array [$j] = $temp; 
      
} 
      
} 
      
} 
      
Print_r ($array); 
      
?> 
     
 
    
This is the write bubble sort algorithm, and the result is OK:
  
   
   

  
   
   

    
    
   ----------PHP Debug----------
   
    
    

   
    
    

      Array 
     
( 
     
[0] => 86 
     
[1] => 56 
     
[2] => 41 
     
[3] => 36 
     
[4] => 15 
     
[5] => 10 
     
[6] => 9 
     
[7] => 8 
     
[8] => 5 
     
[9] => 4 
     
[Ten] => 3 
     
[One] => 2 
     
) 
     
 
    
   
    
    
Output complete (time consuming 0 seconds)-Normal termination
  
   
   

Looking at the small joy of success, and then wrote another, so the problem came out-

  
   
   

   
    
    
 
     

       <?php 
      
$array = Array (10,5,36,86,2,56,9,15,8,4,3,41); 
      
$num = count ($array); 
      
For ($i =0 $i < $num-1; $i + +) { 
      
for ($j = $i +1; $j < $num; $j + +) { 
      
if ($array [$j]> $array [$i]) {//Here is the Exchange key value 
      
$temp = $i; 
      
$i = $j; 
      
$j = $temp; 
      
} 
      
} 
      
} 
      
Print_r ($array); 
      
?> 
     
 
    
The result is appalling ...
  
   
   

 
   
   

    
    ----------PHP Debug----------
    
    
 
    
    

      Array 
     
 ( 
     
 [0] => 10 
     
 [1] => 5 
     
 [2] => 
     
 [3] => 
     
 [4] => 2 
     
 [5] =>, 
     
 [6] => 9 
     
 [7] => 
     
 [8] => 8 
     
 [9] => 4 
     
 [] => 3 
     
 [one] => 
     
) 
     
 
    
 
    
    
 Output complete (time consuming 0 seconds)-Normal termination