Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!convex!uunet!mcvax!dkuug!ambush!ambone!leif
From: leif@ambone.UUCP (Leif Andrew Rump)
Newsgroups: comp.lang.c
Subject: Re^2: QuickC
Message-ID: <140@ambone.UUCP>
Date: 27 Aug 88 15:45:22 GMT
References: <8808261424.AA11504@ucbvax.Berkeley.EDU>
Organization: AmbraSoft A/S (Denmark)
Lines: 37

TURGUT@TREARN.BITNET (Turgut Kalfaoglu) writes:
>square(num)
>int num;
>{
>  num = num*num;
>}

>OK? There is no 'return' statement in the function. However, it works!
>I get '4' as an answer. So I thought maybe it was keeping the result
>of the last operation, so I added some dummy lines,

>square(num)
>int num;
>{
>  int dummy;
>  num = num*num;
>  dummy=222;
>}

>but the call STILL works... Can anyone shed some light onto this?
>WHY does it work?

My answer has not been tested but I'm quite sure that this is the
right answer to your question:

When you call a function i C the parameters is put on the stack. You
function uses the stack to keep the variable num and when the function
return the result is popped from the stack - which (unfortunately(!)
is the temporary variable num! 

   Leif Andrew Rump, Ambrasoft A/S, Roejelskaer 15, DK-2840 Holte (Denmark)
 UUCP: leif@ambone.dk, phone: +45 2424 111; ABC BBS: +45 68 00 544 (2:505/38)

Please note the node-change:                    Ambone, Italian for a pulpit
(The following interpretations emerged          Am_bone, Ambrasoft A/S bone
 when Ambone was put down on paper and          Amb_one, Ambrasoft A/S #one
 accepted - they are solely mine!!!!!)          ...