simple array algorithm

array_inversion.php

<?php 
/**
 * Simple inversion algo
 */

/**
 * Function for string inversion. 
 * @param  string $str just a normal text string
 * @return string $str same string but inverted
 */
function xir_ary_inv( string $str )
{
	$str 			= str_split( $str );
	$max 			= count( $str );
	$middle 		= ( $max % 2 ) ? ( $max - 1 ) / 2 : $max / 2; 

	for ( $i = 0; $i < $middle; $i++ ) 
	{ 
		if ( ( $max % 2 ) == 0 and $i == ( $max / 2 ) ) continue;

		$n = $max - 1;
		$t = $str[ $i ];
		$str[ $i ] = $str[ $n - $i ];
		$str[ $n - $i ] = $t;
	}

	$str = implode( '', $str );
	return $str;
}

echo xir_ary_inv( "Tony" );