reverseArrayWords.php

<?php
/**
 * Reverse Words In Array Of Charachters
 *
 * @param array $input
 *
 * @return array
 */
function reverseWords(array $input) : array
{
    $tWord = [];

    foreach ($input as $index => $c)
    {
        if ( ord($c) == 32 || $flag = ($index == sizeof($input)-1) )
        {
            if ($flag) {
                $tWord[] = $c;
                $i = $index;
            } else {
                $i = $index-1; // replace at index before space appeared
            }

            while ( $t = array_pop($tWord) ) {
                $input[$i-count($tWord)] = $t;
            }

            $tWord = [];

            continue;
        }

        $tWord[] = $c;
    }


    return $input;
}


print_r(
    reverseWords(['I', ' ', 'l','o','v','e',' ','T','a','x','i','f','y'])
);