Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!novavax!twwells!bill
From: bill@twwells.uucp (T. William Wells)
Newsgroups: comp.misc
Subject: Re: The "evil" GOTO (Was: 25 Years of BASIC)
Message-ID: <912@twwells.uucp>
Date: 11 May 89 00:26:31 GMT
References: <1791@ubu.warwick.UUCP> <1436@onion.reading.ac.uk> <1814@ubu.warwick.UUCP> <698@occrsh.ATT.COM> <852@umecs.cs.umu.se>
Reply-To: bill@twwells.UUCP (T. William Wells)
Organization: None, Ft. Lauderdale
Lines: 51
Summary:
Expires:
Sender:
Followup-To:
Distribution:
Keywords:

In article <852@umecs.cs.umu.se> christer@rachel.UUCP (Christer Ericson) writes:
: Rubin states the following problem:
: "Let X be an N x N matrix of integers. Write a program that will print the
: number of the first all-zero row of X, if any."
:
: Along with this he presents the following program with a goto [also two other
: programs w/o gotos that are disgusting to look at]:
:
: [BTW, I reindented the program a bit]
:
: for i:=1 to n do begin
:   for j:=1 to n do
:     if x[i,j]<>0 then goto reject;
:   writeln('The first all-zero row is ',i);
:   break;
: reject:
: end;

Why don't I use Pascal anymore? Because C says it much better. (NB:
array origins have been made 0 and no declarations are shown.)

	for (i = 0; i < N; ++i) {
		for (j = 0; X[i][j] == 0; ) {
			if (++j == N) {
				printf("The first all-zero row is %d\n", i);
				return;
			}
		}
	}

And if one insists on not putting this into its own function (making
the return improper):

	for (i = 0; i < N; ++i) {
		for (j = 0; X[i][j] == 0; ) {
			if (++j == N) {
				printf("The first all-zero row is %d\n", i);
				break;
			}
		}
		if (j == N) {
			break;
		}
	}

One could, of course, turn the first break into a goto, but
eliminating the possible cost of the j == n test isn't worth the loss
of clarity.

---
Bill                            { uunet | novavax } !twwells!bill