Is there a good example of how toupper() works?

[Eric "The Mentat Philosopher" Hendrickson]

Basically, what I want to do is take a string of upper/lower case, and make
it all upper case.  Here is a first try at it,


#include <ctype.h>
main()
{
	char *duh = "Hello";
	printf("%s\n", duh);
	while (*duh <= strlen(duh)) {
		if (islower(*duh)) *duh = toupper(*duh);
		*duh++;
	}
	printf("%s\n", duh);
}

And what I get is :

Hello
Hello

What I want is:

Hello
HELLO

Can anybody point out a good way of doing this?

Thanks much,
			Eric Hendrickson
-- 
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|Eric (the "Mentat-Philosopher") Hendrickson	  Academic Computing Services
|edh at ux.acs.umn.edu	   The game is afoot!	      University of Minnesota
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