Herbert Rosenau wrote in a message to Thomas Seeling:

 HR> No. The only garanteed is: digits are contigous. So '0' through '9'
 HR> can be simple in/decremented. But letters not.

Correct.

 HR> But practise thows tha independant of chasets and real computers it
 HR> would go. And if you don't mix numbers and letters (like 0x41 for
 HR> 'A') and uppercase and lowercase it would be independant of ASCII
 HR> or EBCDIC.

No, EBCDIC letters are not contiguous.

The obvious solution I talked about would of course be:

const char lookuptable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

etc.

greetings,
Tom
tomtorfs@village.uunet.be

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