PHP insertion sort implementation code

I will introduce to you the implementation algorithm and code of PHP insertion sort. Friends in need can refer to it.

Insertion sort is to insert a piece of data into the already sorted ordered data, thereby obtaining a new ordered data with the number plus one.

Algorithm description: ⒈ Starting from the first element, the element can be considered to have been sorted ⒉ Take out the next element and scan from back to front in the sorted element sequence ⒊ If the element (sorted) is larger than the new element, move the element to the next position ⒋ Repeat step 3 until you find the position where the sorted element is less than or equal to the new element ⒌ Insert the new element into the next position ⒍ Repeat step 2 The code is as follows:

<?php
/**
 * php 插入排序
 * site bbs.it-home.org
 * 2013-4-6
*/
    $arr =array(123,0,5,-1,4,15);
    function insertSort(&$arr){
        //先默认第一个下标为0的数是排好的数
        for($i=1;$i<count($arr);$i++){
            //确定插入比较的数
            $insertVal=$arr[$i];
            //确定与前面比较的数比较
            $insertIndex=$i-1;
            
            //表示没有找到位置
            while($insertIndex>=0 && $insertVal<$arr[$insertIndex]){

                //把数后移
                $arr[$insertIndex+1]=$arr[$insertIndex];
                $insertIndex--;
            }

        //插入(给$insertval找到位置了)
        $arr[$insertIndex+1] = $insertVal;
        }
    }
    insertSort($arr);
    print_r($arr);
?>