Add Fraction Math in Pascal (TheRenegadeCoder#4832)

Author: pascalecu

archive/p/pascal/fraction_math.pas

@@ -0,0 +1,199 @@
+program FractionMath;
+
+{$mode objfpc}{$H+}{$modeswitch advancedrecords}
+
+uses
+   Math,
+   SysUtils;
+
+type
+
+   { TFraction }
+
+   TFraction = record
+      Numerator, Denominator: int64;
+
+      procedure Reduce;
+      function ToString: string;
+   class operator +(const A, B: TFraction): TFraction;
+   class operator -(const A, B: TFraction): TFraction;
+   class operator *(const A, B: TFraction): TFraction;
+   class operator /(const A, B: TFraction): TFraction;
+   class operator =(const A, B: TFraction): boolean;
+   class operator <>(const A, B: TFraction): boolean;
+   class operator <(const A, B: TFraction): boolean;
+   class operator <=(const A, B: TFraction): boolean;
+   class operator >(const A, B: TFraction): boolean;
+   class operator >=(const A, B: TFraction): boolean;
+   end;
+
+procedure TFraction.Reduce; inline;
+var
+   Divisor, GcdA, GcdB, Temp: int64;
+begin
+   if Denominator = 0 then
+      raise Exception.Create('Denominator cannot be zero');
+
+   if Numerator = 0 then
+   begin
+      Denominator := 1;
+      Exit;
+   end;
+
+   if Denominator < 0 then
+   begin
+      Denominator := -Denominator;
+      Numerator := -Numerator;
+   end;
+
+   GcdA := Abs(Numerator);
+   GcdB := Denominator;
+
+   while GcdB <> 0 do
+   begin
+      Temp := GcdB;
+      GcdB := GcdA mod GcdB;
+      GcdA := Temp;
+   end;
+
+   Divisor := GcdA;
+
+   // If the GCD is not 1, then simplify the top and the bottom.
+   if Divisor > 1 then
+   begin
+      Numerator := Numerator div Divisor;
+      Denominator := Denominator div Divisor;
+   end;
+end;
+
+function TFraction.ToString: string;
+begin
+   Result := Format('%d/%d', [Numerator, Denominator]);
+end;
+
+class operator TFraction.+(const A, B: TFraction): TFraction;
+begin
+   Result.Numerator := A.Numerator * B.Denominator + B.Numerator * A.Denominator;
+   Result.Denominator := A.Denominator * B.Denominator;
+   Result.Reduce;
+end;
+
+class operator TFraction.-(const A, B: TFraction): TFraction;
+begin
+   Result.Numerator := A.Numerator * B.Denominator - B.Numerator * A.Denominator;
+   Result.Denominator := A.Denominator * B.Denominator;
+   Result.Reduce;
+end;
+
+class operator TFraction.*(const A, B: TFraction): TFraction;
+begin
+   Result.Numerator := A.Numerator * B.Numerator;
+   Result.Denominator := A.Denominator * B.Denominator;
+   Result.Reduce;
+end;
+
+class operator TFraction./(const A, B: TFraction): TFraction;
+begin
+   if B.Numerator = 0 then
+      raise Exception.Create('Division by zero fraction');
+
+   Result.Numerator := A.Numerator * B.Denominator;
+   Result.Denominator := A.Denominator * B.Numerator;
+   Result.Reduce;
+end;
+
+class operator TFraction.=(const A, B: TFraction): boolean;
+begin
+   Result := A.Numerator * B.Denominator = B.Numerator * A.Denominator;
+end;
+
+class operator TFraction.<>(const A, B: TFraction): boolean;
+begin
+   Result := not (A = B);
+end;
+
+class operator TFraction.<(const A, B: TFraction): boolean;
+begin
+   Result := A.Numerator * B.Denominator < B.Numerator * A.Denominator;
+end;
+
+class operator TFraction.>=(const A, B: TFraction): boolean;
+begin
+   Result := not (A < B);
+end;
+
+class operator TFraction.>(const A, B: TFraction): boolean;
+begin
+   Result := B < A;
+end;
+
+class operator TFraction.<=(const A, B: TFraction): boolean;
+begin
+   Result := not (B < A);
+end;
+
+function ParseFraction(const S: string): TFraction;
+var
+   Parts: TStringArray;
+begin
+   Parts := S.Trim.Split(['/']);
+   if Length(Parts) <> 2 then
+      raise Exception.CreateFmt('Invalid fraction format "%s". Expected "num/den"', [S]);
+
+   if not TryStrToInt64(Parts[0].Trim, Result.Numerator) then
+      raise Exception.Create('Invalid numerator');
+
+   if not TryStrToInt64(Parts[1].Trim, Result.Denominator) then
+      raise Exception.Create('Invalid denominator');
+
+   if Result.Denominator = 0 then
+      raise Exception.Create('Denominator cannot be zero');
+
+   Result.Reduce;
+end;
+
+procedure ShowUsage;
+begin
+   Writeln('Usage: ./fraction-math operand1 operator operand2');
+   Halt(1);
+end;
+
+function PerformOperation(const Left: TFraction; const Op: string;
+const Right: TFraction): string;
+begin
+   case Op of
+      '+': Result := (Left + Right).ToString;
+      '-': Result := (Left - Right).ToString;
+      '*': Result := (Left * Right).ToString;
+      '/': Result := (Left / Right).ToString;
+      '==': Result := BoolToStr(Left = Right, '1', '0');
+      '!=': Result := BoolToStr(Left <> Right, '1', '0');
+      '<': Result := BoolToStr(Left < Right, '1', '0');
+      '<=': Result := BoolToStr(Left <= Right, '1', '0');
+      '>': Result := BoolToStr(Left > Right, '1', '0');
+      '>=': Result := BoolToStr(Left >= Right, '1', '0');
+      else
+         raise Exception.CreateFmt('Unknown operator: "%s"', [Op]);
+   end;
+end;
+
+
+var
+   Op: string;
+   LeftOperand, RightOperand: TFraction;
+begin
+   if ParamCount <> 3 then
+      ShowUsage;
+
+   try
+      LeftOperand := ParseFraction(ParamStr(1));
+      Op := ParamStr(2).Trim;
+      RightOperand := ParseFraction(ParamStr(3));
+
+      Writeln(PerformOperation(LeftOperand, &Op, RightOperand));
+   except
+      on E: Exception do
+         ShowUsage;
+   end;
+
+end.