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From: daveh@marob.masa.com (Dave Hammond)
Newsgroups: comp.lang.c
Subject: toupper() side effects (was Re: evaluation order)
Message-ID: <2511ADAD.6056@marob.masa.com>
Date: 16 Sep 89 02:19:23 GMT
Reply-To: daveh@marob.masa.com (Dave Hammond)
Distribution: na
Organization: ESCC,  New York City
Lines: 19

In article <9366@attctc.Dallas.TX.US> bobc@attctc.Dallas.TX.US writes:
>[...] I figured that it would have been simpler to do something like
>
>	while (((ch = toupper(getch())) != 'Y') && (ch !='N'));
>

Note that some implementations of toupper() (SunOS comes to mind)
will return the wrong result if passed a non-lowercase argument.
You'd probably want to expand this line and run an islower()
test on the argument to toupper:

	int temp;
	while ( ((ch = (islower(temp=getch())
			? toupper(temp)
			: temp)) != 'Y') && (ch !='N'));

--
Dave Hammond
daveh@marob.masa.com