How to exit a For-Next in a nested Switch statement?

[PeterZ]

Hi,

Back to basics!

My understanding is that the only way to exit a For-Next loop prematurely is
with the 'break' keyword. How are you supposed to do that if you're inside
a Switch statement? The break keyword will only come out of the switch, not
the for-next loop.
for (int i=0; i<=myArray.Leng th; i++)
{
if (myArray[i] == true)
switch (i)
{
case 0 :
... do somehting
exit the for loop;

case 1 :
... do somehting
exit the for loop;

case 2 :
... do somehting
exit the for loop;
}
}
Cheers,
PeterZ

[Pazu]

Just for saving your time: The following code compiles well, but it is a
U-turn:

for(int i = 0; i<10; i++) {
switch( i ) {
case 0: Console.WriteLi ne("Start"); break;
case 4: {
Console.WriteLi ne("Haf");
break;
};
break;
default: Console.WriteLi ne(i);break;
}
}
Console.WriteLi ne("End");

Produces funny:
Start
1
2
3
Haf
5
6
7
8
9
End

[self]

Perhaps there should be some way of naming blocks of code, so one might
specify to which the break statment applies.

"jgorlick" wrote:

I agree that goto is not ideal, that it even is poor design.

The fact that there continues to be a case when goto is often used means
that it is poor language design. In this specific case, C# does not provide
a way to exit the for (break) without confusing this with the exit case (also
break).

I would suggest that a nested function ala Pascal would provide the ability
to break from the for within the switch. The nested function is the ideal
solution as the function is only intended to be called from within this
function.

While C# doesn't provide nested functions, use a function and figure a way
to not pollute the namespace with this function yourself.

"Michael S" wrote:

I think Oliver hit the mark.
This is how Iwould do it.

And I would never let a goto go live if there was another solution. And each
time I see a goto I start to think. And always I solve them. A goto is the
same as poor design.

Happy Spaghetti
- Michael S

"Oliver Sturm" <ol****@sturmne t.org> wrote in message
news:xn******** ********@msnews .microsoft.com. ..

PeterZ wrote:

>My understanding is that the only way to exit a For-Next loop prematurely
>is
>with the 'break' keyword. How are you supposed to do that if you're
>inside
>a Switch statement? The break keyword will only come out of the switch,
>not
>the for-next loop.

Well, this is really one good example why break isn't much better that
goto. Why don't you just set a flag:

bool endLoop = false;
for (int i = 0; i <= myArray.Length && !endLoop; i++) {
...
switch(i) {
case 0:
// whatever
endLoop = true;
break;
}
}

This way you have a clearly defined loop, you can find out after the loop
why exactly you left it, and you don't go jumping around the program flow
like break does.

I'm not saying never use it - but I do think it should be used only in the
simplest situations where it's absolutely clear what will happen.
Oliver Sturm
--
omnibus ex nihilo ducendis sufficit unum
Spaces inserted to prevent google email destruction:
MSN oliver @ sturmnet.org Jabber sturm @ amessage.de
ICQ 27142619 http://www.sturmnet.org/blog

[raican]

hi,

the way i've exited for loops in the past is to set the loop variable
to the max so the loop drops out naturally on it's next itteration.

i.e.
for (int i=0; i<=myArray.Leng th; i++)
{
if (myArray[i] == true)
switch (i)
{
case 0 :
... do somehting
i = myArray.Length + 1;
break;
case 1 :
... do somehting
i = myArray.Length + 1;
break;
case 2 :
... do somehting
i = myArray.Length + 1;
break;
}
}

i've never had any problems with this method.

hope this helps
:)

[Alvin Bruney - ASP.NET MVP]

i do this too, there is convention that states that code should manipulate
the counter. if you don't care about convention, that's fine

--
Regards,
Alvin Bruney [MVP ASP.NET]

[Shameless Author plug]
The Microsoft Office Web Components Black Book with .NET
Now Available @ www.lulu.com/owc
Forth-coming VSTO.NET - Wrox/Wiley 2006
-------------------------------------------------------

"raican" <go**********@r aican.co.uk> wrote in message
news:11******** **************@ g14g2000cwa.goo glegroups.com.. .

hi,

the way i've exited for loops in the past is to set the loop variable
to the max so the loop drops out naturally on it's next itteration.

i.e.
for (int i=0; i<=myArray.Leng th; i++)
{
if (myArray[i] == true)
switch (i)
{
case 0 :
... do somehting
i = myArray.Length + 1;
break;
case 1 :
... do somehting
i = myArray.Length + 1;
break;
case 2 :
... do somehting
i = myArray.Length + 1;
break;
}
}

i've never had any problems with this method.

hope this helps
:)