รบกวนเซียนPHP หน่อยนะค่ะ โจทย์ง่ายๆแต่นู๋ทำมิได้อ่า T^T

<?php

	$contents = 'F1 dddff F1 ffcc F1'; //นับจำนวน คำว่า F1
$c = substr_count($contents,'F1');
echo "count 'F1' in contents = $c"; //count 'F1' in contents = 3
	
?>

<?php
$string = 'Banana';

for ( $i = 0; $i < strlen($string); $i++ )
{
	$count = -1;
	$text = $string[$i];
	
	for ( $x = 0; $x < strlen($string); $x++ )
	{
		if ( $text == $string[$x] )
		{
			$count++;
		}
	}
	
	if ( $count > 1 )
	{
		echo 'String ' .$text . ' มีตัวซ้ำทั้งหมด ' . ($count + 1) . '<br />';
	}
	else
	{
		echo 'String ' .$text . ' ไม่มีตัวซ้ำ <br />';
	}
}
?>

<?php
$string = 'Banana';

$stringAdd = array();

for ( $i = 0; $i < strlen($string); $i++ )
{
	$count = -1;
	$text = $string[$i];
	
	for ( $x = 0; $x < strlen($string); $x++ )
	{
		if ( $text == $string[$x] )
		{
			$count++;
		}
	}
	
	if ( $count > 1 && ! in_array($text, $stringAdd) )
	{
		$stringAdd[] =  $text;
		echo 'String ' .$text . ' มีตัวซ้ำทั้งหมด ' . ($count + 1) . '<br />';
	}
	elseif ( ! in_array($text, $stringAdd) )
	{
		$stringAdd[] =  $text;
		echo 'String ' .$text . ' ไม่มีตัวซ้ำ <br />';
	}
}
?>

<?php

/**
 * @author Marosdee
 * @copyright 2009
 */

$string = 'Banana';

$stringAdd = array();

for ( $i = 0; $i < strlen($string); $i++ )
{
	$count = 0;
	$text = $string[$i];
	
	for ( $x = 0; $x < strlen($string); $x++ )
	{
		if ( $text == $string[$x] )
		{
			$count++;
		}
	}
	
	if ( $count > 1 && ! in_array($text, $stringAdd) )
	{
		$stringAdd[] =  $text;
		echo 'String ' .$text . ' มีตัวซ้ำทั้งหมด ' . ($count) . '<br />';
	}
	elseif ( ! in_array($text, $stringAdd) )
	{
		$stringAdd[] =  $text;
		echo 'String ' .$text . ' ไม่มีตัวซ้ำ <br />';
	}
}

?>

<?php
$string = "Banana";
$splited = str_split($string);
print_r(array_count_values($splited));
?>

<form action="countstr.php" method="post">
Input String : <input type="text" name="str">
</form>

$String = $_POST['str']