32 lines
785 B
Prolog
32 lines
785 B
Prolog
:- use_module(library(apply)).
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to_gray(N, G) :-
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N0 is N >> 1,
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G is N xor N0.
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from_gray(G, N) :-
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( G > 0
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-> S is G >> 1,
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from_gray(S, N0),
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N is G xor N0
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; N is G ).
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make_num(In, Out) :-
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atom_to_term(In, Out, _),
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integer(Out).
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write_record(Number, Gray, Decoded) :-
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format('~w~10|~2r~10+~2r~10+~2r~10+~w~n',
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[Number, Number, Gray, Decoded, Decoded]).
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go :-
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setof(N, between(0, 31, N), Numbers),
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maplist(to_gray, Numbers, Grays),
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maplist(from_gray, Grays, Decodeds),
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format('~w~10|~w~10+~w~10+~w~10+~w~n',
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['Number', 'Binary', 'Gray', 'Decoded', 'Number']),
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format('~w~10|~w~10+~w~10+~w~10+~w~n',
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['------', '------', '----', '-------', '------']),
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maplist(write_record, Numbers, Grays, Decodeds).
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go :- halt(1).
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