Question

I have structure like this below. Now, I want swap 2 structures.

public struct Pair<T, U>
{
    public readonly T Fst;
    public readonly U Snd;

    public Pair(T fst, U snd)
    {
        Fst = fst;
        Snd = snd;
    }

    public override string ToString()
    {
        return "(" + Fst + ", " + Snd + ")";
    }

    **public Pair<U, T> Swap(out Pair<U, T> p1, Pair<T,U> p2)
    {
        p1 = new Pair<U, T>(p2.Snd, p2.Fst);

        return p1; 
    }**
}

In Main method try this:

        Pair<int, String> t1 = new Pair<int, string>();
        Pair<String, int> t2 = new Pair<string,int>("Anders",13);
        **t1.Swap(out t1,);** //compilator tells -> https://i.stack.imgur.com/dM6P0.png

Parameters on Swap method are different than compilator achive.

Answer 1

There is no need for out parameters here. Just define it as:

public Pair<U, T> Swap()
{
    return new Pair<U, T>(this.Snd, this.Fst);
}

You can then do:

Pair<string, int> t2 = new Pair<string,int>("Anders",13);
Pair<int, string> t1 = t2.Swap();