Code:
<?php
	echo "Enter the number of nouns you like to change its plural: ";
	$f = fopen("php://stdin","r");
	$num = rtrim(fgets($f));
	$input = array($num);
	function Change_Plural($noun)
	{
		switch (true)
		{
			case (substr($noun,-1) == 's'):
			case (substr($noun,-2) == 'sh'):
			case (substr($noun,-2) == 'ch'):
			case (substr($noun,-1) == 'o'):
...