c# singleton
using System; namespace Singleton { // The Singleton class defines the `GetInstance` method that serves as an // alternative to constructor and lets clients access the same instance of // this class over and over. class Singleton { // The Singleton's constructor should always be private to prevent // direct construction calls with the `new` operator. private Singleton() { } // The Singleton's instance is stored in a static field. There there are // multiple ways to initialize this field, all of them have various pros // and cons. In this example we'll show the simplest of these ways, // which, however, doesn't work really well in multithreaded program. private static Singleton _instance; // This is the static method that controls the access to the singleton // instance. On the first run, it creates a singleton object and places // it into the static field. On subsequent runs, it returns the client // existing object stored in the static field. public static Singleton GetInstance() { if (_instance == null) { _instance = new Singleton(); } return _instance; } // Finally, any singleton should define some business logic, which can // be executed on its instance. public static void someBusinessLogic() { // ... } } -------------------------------------------------------------------------------------------------------- class Program { static void Main(string[] args) { // The client code. Singleton s1 = Singleton.GetInstance(); Singleton s2 = Singleton.GetInstance(); if (s1 == s2) { Console.WriteLine("Singleton works, both variables contain the same instance."); } else { Console.WriteLine("Singleton failed, variables contain different instances."); } } } } =======OUTPUT======= Output >> Singleton works, both variables contain the same instance.