C# Union

union.cs

using System;
using System.Runtime.InteropServices;

//  turns out primitive C# union is already doable
//  http://www.xtremedotnettalk.com/tutors-corner/97390-unions.html

[StructLayout(LayoutKind.Explicit)]
public struct MyUnion
{
    [FieldOffset(0)]
    public bool Bool;

    [FieldOffset(0)]
    public int Int;

    [FieldOffset(0)]
    public float Float;

    public static MyUnion Instance;

    static MyUnion()
    {
        Instance = new MyUnion();

        //  this duplicated initialize is necessary to make compiler happy, but it only happen once
        Instance.Bool = false;
        Instance.Int = 0;
        Instance.Float = 0;
    }
}

class Program
{
    static void Main(string[] args)
    {
        MyUnion union = MyUnion.Instance;
        union.Int = 1;

        Console.Write(string.Format("union: bool:{0}, int:{1}, float:{2}", union.Bool, union.Int, union.Float));
    }
}