Add task8 in php

Author: Holger Lösken

README.md

@@ -106,6 +106,7 @@ and return the last `6` non-zero numbers.
 
 Given the follwing function you should suggest what could be improved. There are no other documents explaining why this function has been written or what the purpose is/should be.
 
+**Example in python**
 ```python
 def multiply(x, y):
     if y > 0:
@@ -122,6 +123,22 @@ def multiply(x, y):
 - What can happen when using this with big numbers, f. ex. > 1.000.000?
 - Type hints
 
+### Task 8
+
+Do an in-place mirroring of a one dimensional array. In-place switching is key here as the input array can be very big
+and no additional memory should be occupied - 
+
+**Requirements:**
+
+- In-place mirroring
+- Handle array with even and odd amount of items
+- Do not use the [`array_reverse`](https://www.php.net/manual/de/function.array-reverse.php) function in PHP
+
+**Example:**
+
+- Even amount: `[8,5,1,4]` -> `[4,1,5,8]`
+- Odd amount: `[6,2,7,9,3]` -> `[3,9,7,2,6]`
+
 ## Contribute
 
 Feel free to contribute. Use the issue list to propose new tasks or open PRs. Just provide proper tests

src/php/composer.json

@@ -12,7 +12,8 @@
             "t3/s1.php",
             "t4/s1.php",
             "t5/s1.php",
-            "t6/s1.php"
+            "t6/s1.php",
+            "t8/s1.php"
         ],
         "psr-4": {
             "Tests\\": "tests/"

src/php/t8/s1.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+function mirror(array $numbers): array {
+    $max = max(array_keys($numbers));
+
+    for($i=0; $i<=(floor(count($numbers)/2))-1; $i++) {
+        $tmp = $numbers[$max-$i];
+        $numbers[$max-$i] = $numbers[$i];
+        $numbers[$i] = $tmp;
+    }
+
+    return $numbers;
+}

src/php/tests/T8Test.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use Exception;
+use PHPUnit\Framework\TestCase;
+
+final class T8Test extends TestCase
+{
+    public function testEvenInputAmount(): void
+    {
+        $input = [8,5,1,4];
+        $this->assertSame(array_reverse($input), mirror($input));
+    }
+
+    public function testOddInputAmount(): void
+    {
+        $input = [6,2,7,9,3];
+        $this->assertSame(array_reverse($input), mirror($input));
+    }
+}