how to show checked checkbox based on database value in php

Here is my code:

<?php 
    $results = array();
    $cval = explode(',', $row['fruits']);

?>
<input type="checkbox" name="fruit[]" value="apple" <?php in_array('apple', $cval)?'checked':'' ?>>Apple
<input type="checkbox" name="fruit[]" value="banana" <?php in_array('banana', $cval)?'checked':'' ?>>Banana
<input type="checkbox" name="fruit[]" value="mango" <?php in_array('mango', $cval)?'checked':'' ?>>Mango
<input type="checkbox" name="fruit[]" value="pp" <?php in_array('pp', $cval)?'checked':'' ?>>PP
<input type="hidden" name="id" value="<?php echo $row['id']?>"><br>
<input type="submit" name="update" value="Update"> 

on print_r($cval) it gives : Array ( [0] => banana [1] => mango [2] => pp ) But checked is remain unchecked?

Whats the mistake? Help me