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Structures
f#classes

I'm pretty new to this so sorry if this is too simple.
Suppose we have:

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type ComplexNumber() =
    let mutable real = new float32()    let mutable imaginary = new float32()
    member this.Real with get() = real                              and set(x) = real <-x    member this.Imaginary with get() = imaginary                                       and set(x) = imaginary <-x

let mutable a = ComplexNumber()a.Real <- 1.0fa.Imaginary <- 1.0f
let mutable b = ComplexNumber()
b <- a
b.Real <- b.Real + 1.0f

<i><i>printf "%d" a.Real Now I'm expecting a.Real to be 1.0f, but it is actually 2.0f. Why? I suppose this is because when I do b <- a it's causing a and b to be the same instance of an object. Is there any way of assigning a to b without this happening? I could do b.Real <- a.Real b.Imaginary <- a.Imaginary but, especially for classes with more members, is there a better way?

.

ZFR, This code should work equally well (depending on what you're doing with it) and it's more in keeping with F#'s idioms (at least as I understand them). As far as I understand, you want to avoid mutable members if possible and I think in this case you can. 

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type ComplexNumber(r:float32, i:float32) = 

   member this.Real = r 

   member this.Imaginary = i 

   static member (+) (a1:ComplexNumber, a2:ComplexNumber) = 

      new ComplexNumber(a1.Real + a2.Real, a1.Imaginary + a2.Imaginary)

And then this should work: 

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let a = new ComplexNumber(1.0f, 1.0f) 

let b = a + new ComplexNumber(1.0f, 0.0f)

My humble attempt at assistance.

By on 5/5/2010 2:08 PM ()

Psychic answer:

[link:msdn.microsoft.com]

:)

By on 5/5/2010 12:24 PM ()

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