Unexpected error in switch case and concatenation

Why is the comparison operator being ignored in this switch case statement?

[calvinmicklefinger]

I have the code ...

<?php
// test

$item_101_product_title = "MGT-101"; 
$item_102_product_title = "MGT-102"; 
$item_103_product_title = "MGT-103"; 
$item_104_product_title = "MGT-104"; 
$item_105_product_title = "MGT-105"; 
$item_106_product_title = "MGT-106"; 
$item_107_product_title = "MGT-107"; 
$item_108_product_title = "MGT-108"; 
$item_109_product_title = "MGT-109"; 
$item_110_product_title = "MGT-110"; 
$item_111_product_title = "MGT-111"; 
$item_112_product_title = "MGT-112"; 
$item_113_product_title = "MGT-113"; 

$message = ''; 
$interval = 54;

switch(true){
 case (($interval > 0)) : $message = $message . $item_101_product_title . '<br />'; 
 case (($interval > 21)) : $message = $message . $item_102_product_title . '<br />'; 
 case (($interval > 53)) : $message = $message . $item_103_product_title . '<br />'; 
 case (($interval > 84)) : $message = $message . $item_104_product_title . '<br />'; 
 case (($interval > 115)) : $message = $message . $item_105_product_title . '<br />'; 
 case (($interval > 146)) : $message = $message . $item_106_product_title . '<br />';
 case (($interval > 177)) : $message = $message . $item_107_product_title . '<br />';
 case (($interval > 208)) : $message = $message . $item_108_product_title . '<br />';
 case (($interval > 239)) : $message = $message . $item_109_product_title . '<br />';
 case (($interval > 270)) : $message = $message . $item_110_product_title . '<br />';
 case (($interval > 302)) : $message = $message . $item_111_product_title . '<br />';
 case (($interval > 332)) : $message = $message . $item_112_product_title . '<br />'; break;
}

echo $message;
?>

I expect to get

MGT-101
MGT-102
MGT-103

But, instead, I get ...

MGT-101
MGT-102
MGT-103
MGT-104
MGT-105
MGT-106
MGT-107
MGT-108
MGT-109
MGT-110
MGT-111
MGT-112

Where did I go wrong?

[omoutop]

i don't see anything wrong... strange behavour

have you tried to var_dump your variable and see what you get?

[PCInk]

Switch/Case ignores conditions once one of them has been met (or at least it does in the C programming language). It executes all commands until 'break' is found, even if the next condition is not met.

Once $interval>0 is found, all the code in the block is run. This is why it is adding all the titles.

[omoutop]

PCInk is correct

from php manual:
In a switch statement, the condition is evaluated only once and the result is compared to each case statement.