PHP Exercises: Find the largest value from first, last, and middle elements of a given array of integers of odd length

Last update on May 30 2022 11:41:16 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-104 with Solution

Write a PHP program to find the largest value from first, last, and middle elements of a given array of integers of odd length (atleast 1).

Sample Solution:

PHP Code :

<?php
function test($numbers)
 { 

        $first = $numbers[0];
        $middle_ele = $numbers[sizeof($numbers) / 2];
        $last_ele = $numbers[sizeof($numbers) - 1];
        $max_ele = $first;

        if ($middle_ele > $max_ele)
          {
            $max_ele = $middle_ele;
          }

        if ($last_ele > $max_ele)
          {
            $max_ele = $last_ele;
          }

        return $max_ele;;
 }   

echo test([1]) . "\n";
echo test([1,2,9]) . "\n";
echo test([1,2,9,3,3]) . "\n";
echo test([1,2,3,4,5,6,7]) . "\n";
echo test([1,2,2,3,7,8,9,10,6,5,4]) . "\n";

Sample Output:

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to create a new array length 3 from a given array (length atleast 3) using the elements from the middle of the array.
Next: Write a PHP program to create a new array taking the first two elements from a given array. If the length of the given array is less than 2 then return the give array.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC