Array sorting problems

<?php
$arr = Array (23,3,43,5,56,56,33,5,5);
Insert sort (one-dimensional array)
function Insert_sort ($arr) {
$count = count ($arr);
for ($i =1; $i < $count; $i + +) {
$tmp = $arr [$i];
$j = $i-1;
while ($arr [$j] > $tmp) {
$arr [$j +1] = $arr [$j];
$arr [$j] = $tmp;
$j--;
}
}
return $arr;
}

Select sort (one-dimensional array)
function Select_sort ($arr) {
$count = count ($arr);
for ($i =0; $i < $count; $i + +) {
$k = $i;
for ($j = $i +1; $j < $count; $j + +) {
if ($arr [$k] > $arr [$j])
$k = $j;
if ($k!= $i) {
$tmp = $arr [$i];
$arr [$i] = $arr [$k];
$arr [$k] = $tmp;
}
}
}
return $arr;
}

Bubble sort (one-dimensional array)
function Bubble_sort ($array) {
$count = count ($array);
if ($count <= 0) return false;

for ($i =0; $i < $count; $i + +) {
for ($j = $count-1; $j > $i; $j-) {
if ($array [$j] < $array [$j-1]) {
$tmp = $array [$j];
$array [$j] = $array [$j-1];
$array [$j-1] = $tmp;
}
}
}
return $array;
}

Quick sort (one-dimensional array)
function Quick_sort ($array) {
if (count ($array) <= 1) return $array;

$key = $array [0];
$left _arr = Array ();
$right _arr = Array ();
for ($i =1; $i <count ($array); $i + +) {
if ($array [$i] <= $key)
$left _arr[] = $array [$i];
Else
$right _arr[] = $array [$i];
}
$left _arr = Quick_sort ($left _arr);
$right _arr = Quick_sort ($right _arr);

Return Array_merge ($left _arr, Array ($key), $right _arr);
}

?>

«Show all external variables within PHP program the ascending, descending and reordered functions of the array elements in PHP rsort (), sort (), Asort (), Ksort ()»
The array sort function of PHP
Sort ()
In ascending alphabetical order, case-sensitive, all uppercase letters preceded by lowercase letters

Asort () and Ksort ()
Sort the related array, Asort () to order the value, and Ksort () to sort the code

Rsort (), Arsort (), Krsort ()
Reverse sort function

Natsort ()
Sort the array with the natural sort algorithm

Natcasesort ()
Sort the case-insensitive alphabetical array using the "natural sort" algorithm