41. User key editor
    ~~~~~~~~~~~~~~~
This is a short program which lists all the current user-key definitions, and
not just the red ones. You can then edit them, if you wish, using the cursor
and <Copy> keys as usual. The number of bytes used up by the definitions is
displayed; 239 is the maximum available. This was adapted from an original
which I think was published in "Acorn User". You can omit all spaces in the
listing, if you wish, except those inside quotes. This applies to the BBC B
(& B+ ?) but not the Master or Compact.

 100 MODE7:@%=&902:M%=0:PRINT'"Keylist":FOR K%=0 TO 15
 110 PRINT'" *KEY"K%" ";:A%=K%?&B00:B%=256:FOR T%=0 TO 15
 120 S%=T%?&B00:IF S%>A% AND S%<=B% THEN B%=S%
 130 NEXT:IF B%=256 THEN 170
 140 FOR G%=A% TO B%-1:H%=G%?&B01:M%=M%+1
 150 IF H%>31 THEN VDU H% ELSE VDU 124,H%+64
 160 NEXT
 170 NEXT:@%=&90A:PRINT'';M%;" bytes used." :REM max is 239