6b4bde14e1
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1903 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
69 lines
1.2 KiB
Plaintext
69 lines
1.2 KiB
Plaintext
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:- object(numberlist,
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implements(numberlistp),
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extends(list)).
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:- info([
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version is 1.1,
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author is 'Paulo Moura',
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date is 2007/4/20,
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comment is 'List of numbers predicates.']).
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average([], 0.0).
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average([N| Ns], Average) :-
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average(Ns, 1, N, Average).
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average([], Length, Sum, Average) :-
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Average is Sum / Length.
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average([N| Ns], Lacc, Sacc, Average) :-
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Lacc2 is Lacc + 1,
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Sacc2 is Sacc + N,
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average(Ns, Lacc2, Sacc2, Average).
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min([N| Ns], Min) :-
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min(Ns, N, Min).
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min([], Min, Min).
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min([N| Ns], Aux, Min) :-
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( N < Aux ->
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min(Ns, N, Min)
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; min(Ns, Aux, Min)
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).
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max([N| Ns], Max) :-
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max(Ns, N, Max).
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max([], Max, Max).
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max([N| Ns], Aux, Max) :-
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( N > Aux ->
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max(Ns, N, Max)
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; max(Ns, Aux, Max)
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).
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product(List, Product) :-
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product(List, 1, Product).
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product([], Product, Product).
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product([N| Ns], Acc, Product) :-
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Acc2 is Acc * N,
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product(Ns, Acc2, Product).
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sum(List, Sum) :-
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sum(List, 0, Sum).
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sum([], Sum, Sum).
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sum([N| Ns], Acc, Sum) :-
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Acc2 is Acc + N,
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sum(Ns, Acc2, Sum).
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valid(List) :-
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nonvar(List),
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\+ \+ valid2(List).
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valid2([]).
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valid2([Head| Tail]) :-
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number(Head),
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valid2(Tail).
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:- end_object.
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