44 lines
1.2 KiB
OCaml
44 lines
1.2 KiB
OCaml
(* Signature for complex numbers *)
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signature COMPLEX = sig
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type num
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val complex : real * real -> num
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val negative : num -> num
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val plus : num -> num -> num
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val minus : num -> num -> num
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val times : num -> num -> num
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val invert : num -> num
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val print_number : num -> unit
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end;
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(* Actual implementation *)
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structure Complex :> COMPLEX = struct
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type num = real * real
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fun complex (a, b) = (a, b)
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fun negative (a, b) = (Real.~a, Real.~b)
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fun plus (a1, b1) (a2, b2) = (Real.+ (a1, a2), Real.+(b1, b2))
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fun minus i1 i2 = plus i1 (negative i2)
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fun times (a1, b1) (a2, b2)= (Real.*(a1, a2) - Real.*(b1, b2), Real.*(a1, b2) + Real.*(a2, b1))
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fun invert (a, b) =
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let
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val denom = a * a + b * b
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in
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(a / denom, ~b / denom)
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end
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fun print_number (a, b) =
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print (Real.toString(a) ^ " + " ^ Real.toString(b) ^ "i\n")
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end;
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val i1 = Complex.complex(1.0,2.0); (* 1 + 2i *)
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val i2 = Complex.complex(3.0,4.0); (* 3 + 4i *)
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Complex.print_number(Complex.negative(i1)); (* -1 - 2i *)
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Complex.print_number(Complex.plus i1 i2); (* 4 + 6i *)
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Complex.print_number(Complex.minus i2 i1); (* 2 + 2i *)
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Complex.print_number(Complex.times i1 i2); (* -5 + 10i *)
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Complex.print_number(Complex.invert i1); (* 1/5 - 2i/5 *)
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