Numeric Comparison in switch statement

[Raabi]

Hello geeks!

First time working with numeric comparison, I found myself in dark, as below:



switch (_hours)
{
case _hours = 0:
_hours = 12;
break;
case _hours < 12:
_hours = hours;
break;
case _hours = 12:
_hours = 12;
break;
case _hours > 12:
_hours = (hours - 12);
break;
}


But, the code is not functioning. I don't want to use if .. else construct.
Would anybody kindly straighten this syntax, please! Any explaination, if necessary, would be highly appreciated.

[Iamthejuggler]

I don't think it's possible to have conditionals in a switch statement. I've certainly never seen it done.

[Raabi]

I believe, I have seen numeric comparison in switch statement sometime back. Unofortunately, I don't remember the exact syntax, used there.

I am sure, some AS3 guru will show up with a solution.

[Jeff Wheeler]

I'm pretty sure that's not possible, unfortunately. :-/

[brndn]

http://www.kirupa.com/forum/showthread.php?t=335188&highlight=switch

[Jeff Wheeler]

That's disgusting, but I guess it works. :lol:

[Raabi]

Thanks, brndn, for the reference. I tried it and it works.

Have a good time.

[brndn]

That's disgusting, but I guess it works. :lol:

truely revolting i must say, but it does the trick.

[efos]

That's disgusting, but I guess it works. :lol:
That's what I does. :)

Switch statements compare your argument to each case.

Each case statement is resolved from top to bottom as: if (n == case) {}

If it resolves true, all remaining code is executed; omitting the case lines, and stopping at breaks or returns.



var i:int = 4
switch(true) {
case (i>5):
trace(i+" is greater than 5")
case (i>4):
trace(i+" is greater than 4")
case (i>3):
trace(i+" is greater than 3")
case (i>2):
trace(i+" is greater than 2")
break
case (i>1):
trace(i+" is greater than 1")

}To the compiler, above will read as follows:


var i:int = 4
switch(true) {
case (i>5):
trace(i+" is greater than 5")
case (i>4):
trace(i+" is greater than 4")
case (i>3):
trace(i+" is greater than 3")
case (i>2):
trace(i+" is greater than 2")
break
case (i>1):
trace(i+" is greater than 1")

}

Switch can be abused to do just about anything a series of if...else statements can do; and has the bonus ability to execute multiple conditions with less code.

[Jeff Wheeler]

Yeah, I understood how it worked, I just . . . uh, didn't imagine anybody would ever actually write something so gross. :P

[Krilnon]

For what it's worth, there is syntactic sugar for doing this in other languages like Ruby:
i = 5
case
when i < 7
puts '< 7'
when i == 4
puts '== 4'
else
puts 'nil'
end

# < 7

It just so happens that nobody put a similarly intuitive syntax into AS3.

[Scythe]

Exhibit A:


switch (true)
{
case _hours == 0:
_hours = 12;
break;
case _hours < 12:
_hours = hours;
break;
case _hours == 12:
_hours = 12;
break;
case _hours > 12:
_hours = (hours - 12);
break;
}

Exhibit B:


if (_hours == 0)
_hours = 12;
else if (_hours < 12)
_hours = hours;
else if (_hours == 12)
_hours = 12;
else if (_hours > 12)
_hours = (hours - 12);

Not hard to see which is shorter. And exhibit B can be shortened even further to


if (_hours == 0)
_hours = 12;
else if (_hours < 12)
_hours = hours;
if (_hours > 12)
_hours = (hours - 12);