[RESOLVED] Switch case problem

Anguel

Hi!

I have code like the following with some more cases:

foreach ($char_array as $char)
{
	switch ($char) {
		case ($char=='0'):
		echo "Zero";
		break;
		case ($char=='1'):
		echo "One";
		break;
		case ($char=='2'):
		echo "Two";
		break;
		default :
		echo "-";
		break;
}

Everything works fine but when I enter 0, I always get the echo for the next item, i.e. 1 (One). Every other option works but not the 0. Tried it with UTF-8 encoding and ISO-8859-1. Same result. Also moved the 0 case further down but did not help. PHP version is 5.2.11.

Thanks for any help!

Regards,
Anguel

bradgrafelman

Er... that's not really how the switch/case structure is supposed to look. See the manual page for [man]switch[/man] for more info, but here's an example of how the first case should be written:

    switch ($char) { 
        case '0': 
        echo "Zero"; 
        break; 
        // etc.

Anguel

bradgrafelman;10965150 wrote:
Er... that's not really how the switch/case structure is supposed to look. See the manual page for [man]switch[/man] for more info, but here's an example of how the first case should be written:

Thanks, I will check this once again but I saw some examples using the $char in the || (or) so I thought that this should be ok to use.

mrbaseball34

Anguel;10965153 wrote:
Thanks, I will check this once again but I saw some examples using the $char in the || (or) so I thought that this should be ok to use.

Maybe in the if but never in the switch cases...

bradgrafelman

The way you wrote the code above suggests that you don't know how switch/case statements work.

In a nutshell, the expression inside the switch() conditional is compared with each "case" conditional and, if they are equivalent, the case will be executed.

In your code above, you're making comparisons such as: $char == ($char == '0'), meaning $char is being compared with a logical value (true or false) and not a character ('0', '2', etc.).

bradgrafelman

mrbaseball34;10965154 wrote:
but never in the switch cases...

Well technically that's not true - you certainly can use logical expressions (or any other expression) in the 'case' statements, e.g.:

switch(true) {
    case 1 + 2 == 3:
        echo "Hey - math still works!";
        break;
    default:
        echo "... what happened to math?"
        break;
}

is perfectly valid, as is:

switch(true) {
    case $char == '0':
        echo "Zero";
        break;
    // etc.
}

EDIT: I say it's "technically" true since it doesn't cause a parse error and does achieve the desired result despite it not being a very "good" (or "common", or "accepted", or ... etc.) way of (ab)using the switch() structure.

Anguel

Thanks again for the information! Looks like this solved the problem.
And in another forum I found that one can use a fall-through case in order to implement the same echo for more than one cases:
http://stackoverflow.com/questions/207002/how-to-use-a-switch-case-or-in-php

On the other hand I wonder why there are so many wrong examples on the switch manual page, e.g. here:
http://www.php.net/manual/en/control-structures.switch.php#88248

Regards,
Anguel

bradgrafelman

Anguel wrote:
On the other hand I wonder why there are so many wrong examples o http://www.php.net/manual/en/control...itch.php#88248

Well that's not an "example" per sé - its a user-contributed comment. (A user who appears to have been just as confused as you were in regards to how a switch/case structure works. :p)