CODEWITHSUNDEEP
php
Pepelius
Pepelius

Reputation: 1609

Sorting an array of numbers with for-loop

I have a task of sorting an array of numbers in both ascending and descending order. The challenge is, I can't use the built-in sort function, but loop through the array with for-loops instead.

I am a total newbie when it comes to PHP and this task straight off baffles me. Here is the code I'm supposed to work with:

<?php
  $arr = $_GET['arr'];
  $table = explode(',', $arr);
  
  $count = count($table);
  
  // What I tried to work with, didn't get to work:
  for ($i = 0; $i < $count; $i++) {
      for ($j = $i + 1; $j < $count; $j++) {
          if ($table[$i] > $table[$j]) {
              $temp = $table[$i];
              $table[$i] = $table[$j];
              $table[$j] = $temp;
              $asc = implode("," $temp);
          }
      }
  }
  
  echo "Ascending: $asc";
  echo "Descending: $desc";
?>

Any clue why this doesn't run? At some point, I got the first (largest) number in the array with the echo, but don't really know what broke that either.

Upvotes: 0

Views: 5085

Answers (2)

Carsten Massmann
Carsten Massmann

Reputation: 28206

Move the line

$asc = implode(",", $table);

from its current location below the outer for loop and maybe add the line

$desc = implode(",", array_reverse($table));

to get the descending sort order.

Upvotes: 1

Maik Lowrey
Maik Lowrey

Reputation: 17586

Many ways to make it. One solution you will find in the code below. you will certainly notice that the sorting depends only on one operator. Therefore, you can build a function out of it by specifying the sorting as a parameter. function(array $array, string $sort) {}

DESC

    $arr= array(112,21,130,140,2,42);
    for($i=0; $i<count($arr)-1; $i++)
    {
        for($j=0; $j<count($arr)-1; $j++)
        {
            if($arr[$j] < $arr[$j+1]){
                $temp= $arr[$j+1];
                $arr[$j+1]= $arr[$j];
                $arr[$j]= $temp;
            }
        }

    }
    print_r($arr);

Output:

Array
(
    [0] => 140
    [1] => 130
    [2] => 112
    [3] => 42
    [4] => 21
    [5] => 2
)

ASC

    $arr= array(112,21,130,140,2,42);
    for($i=0; $i<count($arr)-1; $i++)
    {
        for($j=0; $j<count($arr)-1; $j++)
        {
            if($arr[$j] > $arr[$j+1]){
                $temp= $arr[$j+1];
                $arr[$j+1]= $arr[$j];
                $arr[$j]= $temp;
            }
        }

    }
    print_r($arr);

Output

Array
(
    [0] => 2
    [1] => 21
    [2] => 42
    [3] => 112
    [4] => 130
    [5] => 140
)

Upvotes: 1

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