where exactly implicit conversion method be put

Question

public class Faranheit 
{
    public float Digree { get; set; }

    public Faranheit(float f) 
    {
        Digree = f;
    }

    public static implicit operator Celcius(Faranheit f)
    {
        return new Celcius((5.0f / 9.0f) * (f.Digree - 32));
    }

    public static implicit operator Faranheit(Celcius c)
    {
        return new Faranheit((9.0f / 5.0f) * c.Digree + 32);
    }
}

public class Celcius
{
    public float Digree{get;set;}

    public Celcius(float c)
    {
        Digree = c;
    }

}

I am just confused, where to put the conversion methods exactly..

It works fine even if I put one method in one class and other in the other, or I interchange them or even if I put both of them in any of the two classes..

But if I put it outside these two classes it doesn't work (compile error)..

Could please someone put some light on this..

EDIT:

if it allows the conversion methods to be in either of the class, why doesn't it allow the conversion method to be in a separate class??

refer http://stackoverflow.com/questions/3672742/cast-class-into-another-class-or-convert-class-to-another — Romil Kumar Jain, May 14 '12 at 17:11
@AdamV: that's not what I am talking about..I don't think that's the reason for my problem.. ;) — techBeginner, May 14 '12 at 17:12
@dotNETbeginner: that's why I wrote this as a comment and not as an answer. :) — Adam V, May 14 '12 at 17:13

score 2 · Answer 1 · answered May 14 '12 at 17:14

All that matters is that the implicit conversion exists in one of the two classes. I would tend to put both conversions in the less-commonly used class.

In this case, the classes look equal, so I would put the conversion to the class in each class i.e. the conversion from F to C would go in the Celsius class, and vice versa.

Really, it's mostly about personal preference.

In this specific case, I would write a Temperature class that lets you get the temperature in C, F, K, R, etc. But that isn't exactly relevant to the actual question.

My question actually is, if it allows the conversion methods to be in either of the class, why doesn't it allow the conversion method to be in a separate class?? — techBeginner, May 15 '12 at 06:42

Phillip Schmidt · Answer 2 · 2012-05-14T17:13:52.120

-1

I would put them in each of the classes. So you can do stuff like:

Celsius c = new Celsius(Value);
Fahrenheit f = c.toFahrenheit();
Celsius newC = f.toCelsius();

edit: or if you wanted to go the Helper class route, you could do:

public static class ConvertTemps
{
    public static Celsius toCelsius(Fahrenheit F)
    {
        return new Celsius(5/8* F - 32);
    }
    public static Fahrenheit toFahrenheit(Celsius C)
    {
        return new Fahrenheit(8/5*C + 32);
    }
}

and then you could do things like:

Celsius c = new Celsius(value);
Fahrenheit f = ConvertTemps.toFahrenheit(c);

But I'd go the first route.

edited May 14 '12 at 17:13

answered May 14 '12 at 17:08

Phillip Schmidt

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Ah, I overlooked that. Good point. Guess that's a pretty important one. Well, given that, you definitely want one in each class. – Phillip Schmidt May 14 '12 at 17:16

where exactly implicit conversion method be put

2 Answers2