RoundToMultiple method

Project: Fractions

Unit: DelphiDabbler.Lib.Fractions

Record: TFraction

Applies to: ~>0.1

function RoundToMultiple(const F: TFraction): TFraction;

Description

This method rounds the fraction to the nearest whole number multiple of the given fraction F and returns the result.

For example, if you round 11/16 to a whole number multiple of 1/8 the result is 6/8.

RoundToMultiple can be useful if you have performed a calculation using fractions but want the result accurate to a certain degree, for example the nearest eighths or sixteenths. It is also useful for converting floating point numbers to fractions with the required accuracy, for example to express π as a fraction to the nearest seventh.

Example

Express π in terms of fractions to the nearest 1/N where N = 1 to 10.

var
  FPi, FRound: TFraction;
  N: Integer;
begin
  FPi := PI;  // Pi is automatically converted to fraction
  for N := 1 to 10 do
  begin
    FRound := FPi.RoundToMultiple(TFraction.Create(1, N));
    WriteLn(
      Format(
        'Pi in terms of 1/%d = %d/%d',
        [N, FRound.Numerator, FRound.Denominator]
      )
    );
  end;
end;

See Also

• TruncateToMultiple method