toupper() side effects (was Re: evaluation order)

[Dave Hammond]

In article <9366 at attctc.Dallas.TX.US> bobc at 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 at marob.masa.com