2017-09-23 10:01:46 +02:00
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open Num
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2020-02-17 23:21:07 -08:00
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let fib =
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let rec fib_aux f0 f1 = function
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| 0 -> f0
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| 1 -> f1
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| n -> fib_aux f1 (f1 +/ f0) (n - 1)
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in
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fib_aux (num_of_int 0) (num_of_int 1)
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2015-11-18 06:14:39 +00:00
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2020-02-17 23:21:07 -08:00
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(* support for negatives *)
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2015-11-18 06:14:39 +00:00
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let fib n =
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2020-02-17 23:21:07 -08:00
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if n < 0 && n mod 2 = 0 then minus_num (fib (abs n))
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else fib (abs n)
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2017-09-23 10:01:46 +02:00
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;;
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2020-02-17 23:21:07 -08:00
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(* It can be called from the command line with an argument *)
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(* Result is send to standart output *)
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let n = int_of_string Sys.argv.(1) in
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print_endline (string_of_num (fib n))
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