C#

// .NET Singleton
sealed class Singleton 
{
    private Singleton() {}
    public static readonly Singleton Instance = new Singleton();
}

sealed class SingletonCounter {
    public static readonly SingletonCounter Instance = 
         new SingletonCounter();
    private long Count = 0;
    private SingletonCounter() {}
    public long NextValue() {
        return ++Count;
    }
}

class SingletonClient {
    [STAThread]
    static void Main() {
        for (int i=0; i<20; i++) {
            Console.WriteLine("Next singleton value: {0}", 
                SingletonCounter.Instance.NextValue());
        }
    }
}