Path: csiph.com!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: Effective uses of c `goto' statement Date: Sun, 06 Dec 2020 05:03:00 -0800 Organization: A noiseless patient Spider Lines: 35 Message-ID: <86ft4jkry3.fsf@linuxsc.com> References: <87czzszjhs.fsf@fedora.osfans.org> <20201202120809.633@kylheku.com> <86sg8kkyjb.fsf@linuxsc.com> <_CPyH.64249$7D7.63135@fx03.iad> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: reader02.eternal-september.org; posting-host="048215ee9820886844dd3aade67dded3"; logging-data="3192"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX196l0EQct6L8efzfPQSujlcld1jNUU5ccQ=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:gIhUk4cGQaORx+OVgIco0oHBYZQ= sha1:hz64nyTRdImUrrd5vNMPCkMghoU= Xref: csiph.com comp.lang.c:156972 Richard Damon writes: > On 12/5/20 11:28 AM, Tim Rentsch wrote: > >> Kaz Kylheku <563-365-8930@kylheku.com> writes: >> >> [...] >> >>> Finite automata re easily implemented without goto, but only goto >>> offers the most efficient possible representation with the fewest >>> state variables (possibly with no state variable at all). >> >> Unless you can offer some sort of argument supporting this >> assertion, I'm inclined to believe it is not the case. > > Well, you can build the Finite automata where the state you are in > is the last label you did a 'goto' to (with an optimization that if > it is the next lable, the goto can be implied). That basically > eliminates the state variable (maybe some state works better in a > state variable if you have a series of states that are similar and > just use a counter). Yes, I understood that already. > The non-goto method is typically a switch statement based on the > state variable, all in a while loop. There each state changes the > variable and breaks from the switch, and then loops in the while to > go to the next state. A common way to implement a state machine is with a switch() inside a loop of some sort (e.g., for() or while()). I got that already also. My question is about other possibilities that do not use goto but also do not use state variables.