namespace State_DesignPattern {   using System;   abstract  class State    {     protected  string strStatename;         abstract  public  void Pour();     // do something state-specific here    }     class OpenedState : State    {         public OpenedState ()     {      strStatename =  " Opened " ;    }      override  public  void Pour()     {      Console.WriteLine( " pouring " );      Console.WriteLine( " pouring " );      Console.WriteLine( " pouring " );    }   }      class ClosedState : State    {         public ClosedState()     {      strStatename =  " Closed " ;    }      override  public  void Pour()     {      Console.WriteLine( " ERROR - bottle is closed - cannot pour " );    }   }     class ContextColaBottle    {     public  enum BottleStateSetting {      Closed,      Opened    } ;     // If teh state classes had large amounts of instance data,     // we could dynamically create them as needed - if this demo     // they are tiny, so we just create them as data members      OpenedState openedState =  new OpenedState();    ClosedState closedState =  new ClosedState();     public ContextColaBottle ()     {       // Initialize to closed        CurrentState = closedState;    }       private State CurrentState;         public  void SetState(BottleStateSetting newState)     {       if (newState == BottleStateSetting.Closed)       {        CurrentState = closedState;      }        else        {        CurrentState = openedState;      }     }       public  void Pour()     {      CurrentState.Pour();    }     }      ///  <summary>    ///   Summary description for Client.   ///  </summary>    public  class Client   {     public  static  int Main( string [] args)     {      ContextColaBottle contextColaBottle =  new ContextColaBottle();      Console.WriteLine( " initial state is closed " );      Console.WriteLine( " Now trying to pour " );       contextColaBottle.Pour();      Console.WriteLine( " Open bottle " );      contextColaBottle.SetState(ContextColaBottle.BottleStateSetting.Opened);      Console.WriteLine( " Try to pour again " );      contextColaBottle.Pour();       return  0 ;    }   } }