double kgValue;
double lbValue;

// Simple programmatic approach to conversion, using string `Synonyms`
var kgToLbs = new MassConverter("kg", "lbs");
kgValue = 452;
lbValue = kgToLbs.LeftToRight(kgValue);
Console.WriteLine("452kg in pounds is " + lbValue);

// Converting both ways is easy
kgValue = kgToLbs.RightToLeft(lbValue);
Console.WriteLine("Converted back: " + kgValue);

// Rounding is part of conversion
lbValue = kgToLbs.LeftToRight(kgValue, 2);
Console.WriteLine("452kg in pounds (to 2 decimal places) is " + lbValue);

// You can easily customise converters to support Synonyms used in
// business logic, such as those stored on a database
kgToLbs.AddSynonym("kg", "MTOW (KG)");

kgValue = 3000;
kgToLbs.UnitLeft = "MTOW (KG)";
lbValue = kgToLbs.LeftToRight(kgValue);
Console.WriteLine("3000 MTOW (KG) in lbs is " + lbValue);

// Add a new unit with a custom conversion factor
kgToLbs.AddUnit("Chuck Norris", 9001);
kgToLbs.UnitRight = "Chuck Norris";
kgValue = 7;
var chucks = kgToLbs.LeftToRight(kgValue);
Console.WriteLine("7kg is equal to " + lbValue + " chucks");

public class DistanceConverter : BaseUnitConverter 
{
    UnitFactors units = new UnitFactors("m") 
    {
        { new UnitFactorSynonyms("m", "metre"), 1 },
        { new UnitFactorSynonyms("km", "kilometre"), 0.001 },
        { new UnitFactorSynonyms("cm", "centimetre"), 100 },
        { new UnitFactorSynonyms("mm", "millimetre"), 1000 },
        { new UnitFactorSynonyms("ft", "foot", "feet"), 1250d / 381 },
        { new UnitFactorSynonyms("yd", "yard"), 1250d / 1143 },
        { "mile", 125d / 201168 }, // strings automatically cast to UnitFactorSynonyms
        { new UnitFactorSynonyms("in", "inch"), 5000d / 127 },
    };

    public DistanceConverter(string leftUnit, string rightUnit) 
    {
        Instantiate(units, leftUnit, rightUnit);
    }
    public DistanceConverter() 
    {
        Instantiate(units);
    }
}