Paul E Condon wrote: > but 2 are non printing: 0x20 and 0x7F > I leave the last step as an exercise for the reader. ;-)
I hate to make this thread longer... Sigh. Whether something is printable or not was easier to see in the old days when printers had dot matrix or daisy wheels or selectric balls or other such loud and visible print heads. If you emitted a printable character the head moved forward. If you emited a non-printable character the head did not move forward. Using that definition space is definitely a printable character since it moves the print head forward. We are all agreed that it is invisible. But being invisible is not part of the definition of whether it is printable or not. DEL 0x7f is a control character. It is not a printable character. And its history is interesting. You can see this for yourself. $ printf "a\x20b\n" | od -tx1 0000000 61 20 62 0a $ printf "a\x20b\n" a b Space was printed in the above. Space is a printable, if invisible, character. $ printf "a\x7fb\n" | od -tx1 0000000 61 7f 62 0a $ printf "a\x7fb\n" ab DEL was not printed, did not move the head forward, a was followed immediately by b, DEL is not a printable character. Bob
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