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36 lines
589 B
Mathematica
36 lines
589 B
Mathematica
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% vim: ft=mercury ts=4 sw=4 et
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:- module fib.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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:- implementation.
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:- import_module int.
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:- import_module list.
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:- import_module require.
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:- import_module string.
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main(!IO) :-
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N = 46,
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fib(N, F),
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io.format("fib(%d) = %d\n", [i(N), i(F)], !IO).
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:- pred fib(int::in, int::out) is det.
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fib(N, F) :-
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( if N < 0 then
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error("fib(N, _): N must be greater than 0")
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else if ( N = 0 ; N = 1 ) then
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F = 1
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else
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fib(N-1, FA),
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fib(N-2, FB),
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F = FA + FB
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).
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