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Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Lew Pitcher <lew.pitcher@digitalfreehold.ca> Newsgroups: comp.lang.c Subject: Re: Checking the loop variable after the loop has ended (Was: Loops (was Re: do { quit; } else { })) Date: Thu, 17 Apr 2025 22:29:26 -0000 (UTC) Organization: A noiseless patient Spider Lines: 35 Message-ID: <vtrvc6$mjoi$1@dont-email.me> References: <vspbjh$8dvd$1@dont-email.me> <87ikn3zg18.fsf@nosuchdomain.example.com> <vtqnv9$hf83$1@dont-email.me> <87fri68w2c.fsf@nosuchdomain.example.com> <vtrrdi$1smfe$1@news.xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Fri, 18 Apr 2025 00:29:26 +0200 (CEST) Injection-Info: dont-email.me; posting-host="15b376c78d30a238acea0483949cc1b8"; logging-data="741138"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18F07V3lqG80zd78j2qLSGNPWU3Rw8Pch8=" User-Agent: Pan/0.139 (Sexual Chocolate; GIT bf56508 git://git.gnome.org/pan2) Cancel-Lock: sha1:/gTaTyoxHF/lEmzDdoX//s1p5fU= Bytes: 2580 On Thu, 17 Apr 2025 21:21:54 +0000, Kenny McCormack wrote: > In article <87fri68w2c.fsf@nosuchdomain.example.com>, > Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote: > ... >>IMHO it doesn't much matter what the value is after the loop ends, but >>any standard for a language with such a feature should either restrict >>the scope to the loop, specify the value the variable has after the >>loop, or explicitly say that it's unspecified or undefined. > > I frequently check the value of the loop variable after the loop has ended > in order to determine if the loop ended "normally" or prematurely via > "break". E.g., > > for (i=0; i<10; i++) { code that might or might not break } > if (i == 10) puts("It ended normally"); It's also a handy idiom for a compact list search loop where the terminating condition is either end of the list, or a matched entry. If the cursor isn't the end-of-list marker, then it references the matched entry; for (n = NUM_ENTRIES; (n >= 0) && (node[n] != key); --n) continue; if (n != -1) printf("Found key at entry %d\n",n); > I've applied this method in many C and (vaguely) C-like languages. > Any language with a "for" type loop, where you can check the value after > the loop can avail themselves of this method. I concur :-) -- Lew Pitcher "In Skills We Trust"