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From: frank@zen.co.uk (Frank Wales)
Newsgroups: comp.lang.c
Subject: Dubious C code
Keywords: for switch in case do bananas
Message-ID: <1508@zen.UUCP>
Date: 6 Feb 89 18:46:48 GMT
Organization: Zengrange Limited, Leeds, England
Lines: 44

A colleague of mine [honest, it wasn't me] was in the process of
chopping some code around, and accidentally got the equivalent of the
following section of code past the C compiler without any trouble.  It
lints completely clean, too.  The question is, *should* it compile
without any complaints at all?  A case can be made (sic) by analogy to
statement labels, but I think the compiler should have enough semantic
smarts to say, "waaaait a minute, pal!"  Have a look yourself:

.................................. rainbow.c ..................................
#include <stdio.h>

main()
{
  int zippy,bungle,george=99;

  for (zippy=0;zippy<4;++zippy)
  {
    switch(zippy)
    {
    case 0:
      bungle = 0;
      break;
    case 2:
      for (george=10;george>bungle;--george)
      /* falls through */
    case 1:
      (void)puts("Bananas!");
      break;
    default:
      (void)puts("\"Time for bed,\" said Geoffrey.");
    }
  }
  return(0);
}
...............................................................................
    
[System: HP-9000 model 840 rel 2.1 -- lint is pcc-based, compiler is not.]

Now, guess how many times "Bananas!" should get printed.  Please write the
answer on a postcard and put it in a drawer.  :-)
    
--
Frank Wales, Systems Manager,        [frank@zen.co.uk<->mcvax!zen.co.uk!frank]
Zengrange Ltd., Greenfield Rd., Leeds, ENGLAND, LS9 8DB. (+44) 532 489048 x217