17 lines
407 B
Ada
17 lines
407 B
Ada
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function Fib (X: in Integer) return Integer is
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function Actual_Fib (N: in Integer) return Integer is
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begin
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if N < 2 then
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return N;
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else
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return Actual_Fib (N-1) + Actual_Fib (N-2);
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end if;
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end Actual_Fib;
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begin
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if X < 0 then
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raise Constraint_Error;
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else
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return Actual_Fib (X);
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end if;
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end Fib;
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