Re: 2.2.18 signal.h

[Thomas Dodd <ted@cypress.com>]

Andrea Arcangeli wrote:
> 
> On Fri, Dec 15, 2000 at 05:55:08PM -0200, Rik van Riel wrote:
> > On Fri, 15 Dec 2000, Andrea Arcangeli wrote:
> >
> > > x()
> > > {
> > >
> > >     switch (1) {
> > >     case 0:
> > >     case 1:
> > >     case 2:
> > >     case 3:
> > >     ;
> > >     }
> > > }
> > >
> > > Why am I required to put a `;' only in the last case and not in
> > > all the previous ones?
> >
> > That `;' above is NOT in just the last one. In your above
> > example, all the labels will execute the same `;' statement.
> >
> > In fact, the default behaviour of the switch() operation is
> > to fall through to the next defined label and you have to put
> > in an explicit `break;' if you want to prevent `case 0:' from
> > reaching the `;' below the `case 3:'...
> 
> Are you kidding me?

Absolutely NOT.

switch (x) {
  case 0:
  case 1:
      printf ("%d\n", x);
      break;
  case 2:
      printf ("%d\n",x*x);
  case 3:
      printf ("%d\n", x*x*x);
 }

if x==0 or 1, prints x (the 0 or one),
if x==2 , it prints 4 and 8  since no break statement exits the switch,
if x==3, it prints only 27,
any othe value of x, and nothing is printed.

Every C compile I have ever used does this.
Sun's C and C++, HP's C, Microsoft's VC++, Borland's C, and all versions
of gcc and g++.

Grab any C programming book, and find the switch statement.

	-Thomas
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