tedd schreef:
At 6:46 PM -0600 8/31/08, Govinda wrote:
Not that it is an issue, but just to understand the logic-
Why do we have to use 'break' statements in each case?
switch ($i) {
case 0:
echo "i equals 0";
break;
case 1:
echo "i equals 1";
break;
case 2:
echo "i equals 2";
break;
}
all 3 cases fire, even though $i only equals ONE of those case values
(if I said that right).
I mean if $i==1, then in other languages I don't expect the first or
last case to fire! (?)
Is the purpose just so one has the OPTION of letting them all fire,
and turning that off with 'break'?
Or is there a better reason?
-G
The "break" is to separate each case (i.e., condition)
The switch ($i) isn't even needed if you do it like this:
switch (true)
{
case $i==0:
echo "i equals 0";
break;
case $i==1:
echo "i equals 1";
break;
case $i==2:
echo "i equals 2";
break;
}
this is 'true' ;-) and works very well when you want to
check disparate truths but there are caveats:
1. it's less performant IIRC
2. there is no type checking, so auto-casting occurs during the
test of each case's expression
3. it will become even less performant ... someone clever sod has
a patch that heavily optimizes 'simple' switch statements ... see
the internal mailing list archives for details (I can't remember the
details) ... I gather this patch will eventually make it into the core,
if it hasn't already.
If you wanted to combine conditions, you could do this:
switch (1)
{
case $i==-2:
case $i==-1:
case $i==0:
echo "i is less than 0 but greater than -3 and is a counting number
(i.e., no fraction)";
break;
case $i==1:
echo "i equals 1";
break;
case $i==2:
echo "i equals 2";
break;
}
Typed without checking and after my vacation.
Cheers,
tedd
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