PHP: trying to substract the returning values from strpos()

i have开发者_开发知识库 this code:

<?php var_dump(strpos($url, "cashgold.")+9) ?>

<?php var_dump(strpos($url, '/', 8)) ?>

<?php $resta = strpos($url, '/', 8) - strpos($url, "cashgold.")+9 ?>

<?php var_dump($resta) ?>

this prints:

20 22 20

I expected it prints :

20 22 2

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I think you're having issues with maths - specifically with operator precedence.

When you're doing

<?php $resta = strpos($url, '/', 8) - strpos($url, "cashgold.")+9 ?>

you're doing (22 - 11) + 9. This is because + and - are the same precedence, so it's being evaluated left to right.

Try (note the brackets)

<?php $resta = strpos($url, '/', 8) - (strpos($url, "cashgold.")+9) ?>

to do the calculation you're after.

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Sorry i should write:

(strpos($url, "cashgold.")+9)