CODEWITHSUNDEEP
c#operator-overloadingimplicit-conversion
Tyler Pantuso
Tyler Pantuso

Reputation: 853

Can I make this implicit conversion from an operator overload work?

I am trying to overload the division operator in a class to return a double.

I have two classes: Length and Angle. In the Angle class, I have initializers that accept different trigonometric ratios. Here's an example:

public class Angle
{
    public double Degrees;
    public double Minutes;
    public double Etc;

    public Angle(double radians)
    {
        // Main initialization here.
    }

    public static Angle FromTangent(double tangent)
    {
        return new Angle(Math.Atan(tangent));
    }
}

The Length class converts a measurement input into different units of measure. The last method would really make life easy:

public class Length
{
    public double Inches;
    public double Feet;
    public double Meters;
    public double Etc;

    public enum Unit { Inch, Foot, Meter, Etc };

    public Length(double value, Unit unit)
    {
        // Main initialization here.
    }

    public static Length operator /(Length dividend, Length divisor)
    {
        double meterQuotient = dividend.Meters / divisor.Meters;
        return new Length(meterQuotient, Unit.Meter);
    }

    // This is what I want to be able to do.
    public static double operator /(Length dividend, Length divisor)
    {
        double ratio = dividend.Meters / divisor.Meters;
        return ratio;
    }
}

The problem is that the last two methods are ambiguous. I did some research, and implicit conversion seems like the right learning path. I have tried the following methods, which do not seem to be in the correct syntax:

    public static implicit operator double /(Length dividend, Length divisor) { }

    public static double implicit operator /(Length dividend, Length divisor) { }

    public static implicit double operator /(Length dividend, Length divisor) { }

Ultimately

I want to be able to divide two Length objects, and get a double. It is only valid for division though, because it returns a ratio, not a number of units. If this is possible, the implementation would be super easy, and awesome. That's why I want to know if this is possible.

Length opposite = new Length(userInputValue, userSelectedUnitOfMeasure);
Length adjacent = new Length(otherInputValue, otherUnitOfMeasure);

Angle angle = Angle.FromTangent(opposite / adjacent); // ← So cool if this is possible

Can this be done while still being able to keep my other division operator overload?

Upvotes: 0

Views: 94

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1503839

A conversion isn't a division - those are two separate operations. You appear to be trying to combine them at the moment.

Fundamentally, it seems that you should remove this operator:

// Kill this
public static Length operator /(Length dividend, Length divisor)

It simply doesn't make sense - as you mentioned, a length divided by a length is a ratio, it's not a length. 5m / 2m is 2.5, not 2.5m.

Once this is removed, there's no ambiguity, so you're fine.

On the other hand, having fields for inches, feet, metres etc seems like a bad idea to me. You may want to have two fields, one of which is the magnitude and the other of which is the unit (probably an enum).

Upvotes: 4

Related Questions