Pelles C forum

C language => Beginner questions => Topic started by: ahsjar on June 15, 2007, 09:53:29 AM

Title: switch case
Post by: ahsjar on June 15, 2007, 09:53:29 AM

hello,
shouldn't this work?

Code: [Select]

switch (x)
{
    case a:
    case b:
    case c:
         ...;
         break;
    case d:
         ...;
         break;
    case e:
         ...;
         break;
}
but i am getting the following error (for lines at "case b:" and "case c:")
error #2001: Syntax error: found ':' - expecting ';'.
error #2061: Illegal statement termination.


ahsjar

Title: Re: switch case
Post by: frankie on June 15, 2007, 10:45:41 AM

In the switch statement the cases must be constant integers.
In your code a, b, c, etc are constant integers?
The use of multiple cases with the same body is perfectly legal.

Title: Re: switch case
Post by: ahsjar on June 15, 2007, 11:50:05 AM

thanks for the quick reply..

yes, they are constant integers and i tested it - in the same code this works:

switch (x)
{
    case a:
         ...;
         break;
    case b:
         ...;
         break;
    case c:
         ...;
         break;
}
 
and this doesn't:

switch (x)
{
    case a:
    case b:
    case c:
         ...;
         break;
}

hmm... i wonder what it is?  ???

Title: Re: switch case
Post by: frankie on June 15, 2007, 12:17:33 PM

This sample:

Code: [Select]

int a,b,c,d, x;

x='a';
a=b=c=d='x';

switch(x)
{
case 'a':
case 'x':
case 'z':
case 'f':
case 'j':
case 'w':
case 'y':
a=b;
break;
case 'b':
b=c;
break;
case 'c':
c=d;
break;
case 'd':
d=a;
break;
}
printf("%d%d%d%d%d", a, b, c, d, x);

switch(x)
{
case 'a':
case 'b':
case 'c':
case 'd':
d=a;
break;
}
Works without problems here.
What really are a, b, c etc?
This snippet gives a similiar error:

Code: [Select]

#define d 'd':

switch(x)
{
case 'a':
case 'b':
case 'c':
case d:
c=a;
break;
}
Could you post a snippet of your code, possibly a simple project with the options you have set.

Title: Re: switch case
Post by: ahsjar on June 15, 2007, 05:08:10 PM

hey Frankie!
sorry i took your time... the problem was that i was staring at the screen so long that i just didn't see that i wrote:

case a:
       b:
       c:
       ...;
       break;

but this looks interesting:

Code: [Select]

#define d 'd':

switch(x)
{
case 'a':
case 'b':
case 'c':
case d:
c=a;
break;
}
well, now i repaired it and it works! it seems i have to learn how to look at the things (not just code). sorry once again and thanks!

ahsjar