Robert Cummings wrote:
> Nathan Rixham wrote:
>> Robert Cummings wrote:
>>> steve_r wrote:
>>>> I'm new to programming, drive a truck in the day, now taking night
>>>> courses
>>>> to get a better job for my family. Please bear with me if this is a
>>>> dumb
>>>> question, I don't have much experience.
>>>>
>>>> I'm taking a night class in HTML and PHP and can't figure out a
>>>> problem and
>>>> can't find the answer in the book for the course ("Beginning PHP5" by
>>>> Wrox
>>>> Press), on the switch manual page on php.net, or in any postings to
>>>> this
>>>> mailing list.
>>>>
>>>> I'm trying to pass a value to a simple integer to a function, and then
>>>> use
>>>> that value in a switch statement. The problem I'm having is that
>>>> regardless
>>>> of the value of 'val', the first case statement always executes. Even
>>>> if I
>>>> put '$val = 0' right before the case statement, the first case
>>>> statement
>>>> executes. The syntax looks correct based on the php.net man page for
>>>> switch
>>>> and from the user examples. It also matches the example in the book.
>>>>
>>>> function check_it2($val) {
>>>> echo gettype($val);
>>>> switch($val) {
>>>> case($val > 0 ):
>>>> echo "Switch greater than 0";
>>>> $diff_obj = 1;
>>>> break;
>>>> case($val < 0 ):
>>>> echo "Less than 0";
>>>> $diff_obj = -1;
>>>> break;
>>>> default:
>>>> echo "Equal to 0";
>>>> $diff_obj = 0;
>>>> }
>>>> print("Here's \$diff_obj2 in the function: " . $diff_obj);
>>>> return $diff_obj;
>>>> }
>>> You're a tad confused :)
>>>
>>> Q: What is the result of $val > 0?
>>> A: false.
>>>
>>> Q: What is the value of $val?
>>> A: 0
>>>
>>> Q: Is 0 equivalent to false?
>>> A: Yes!
>>>
>>> Use an if statement for this kind of logic.
>>
>> This is a fantastic example of false logic and an easy pitfall.
>>
>> in fact this would make a great interview question!
>>
>> to expand a little on the various scenarios (just for clarity, Rob is
>> right)
>>
>> $val = 1;
>> 1 > 0 equates to TRUE
>> is 1 equivalent to TRUE : YES
>>
>> $val = 0;
>> 0 > 0 equates to FALSE
>> is 0 equivalent to FALSE : YES
>>
>> $val = -1;
>> -1 > 0 equates to FALSE
>> is -1 equivalent to FALSE: YES
>>
>> so no matter what value you set $val to; it's always true.
>
> Fail on that last one. -1 is not equivalent to FALSE :B
>
well that's one job I'm not getting :p
cheers for the picking that one up Rob
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