using System;

public class StatePattern {
	public static void Main(string[] argv) {
		Context c = new Context("my Context");
		
		StateA sa = new StateA();
		StateB sb = new StateB();
		
		c.State = sa;
		c.Method(argv);
		
		c.State = sb;
		c.Method(argv);
	}
}

public abstract class State {
	private string _name;
	
	public State(string name) {
		this._name = name;
	}
	
	public override string ToString() {
		return this._name;
	}
	
	public abstract void Method(Context c, string[] args);
}

public class StateA : State {
	public StateA() : base("StateA") {
	}
	
	public override void Method(Context c, string[] args) {
		Console.WriteLine("{0} ({1}): {2}", this, c, String.Join(", ", args));
	}
}

public class StateB : State {
	public StateB() : base("StateB") {
	}
	
	public override void Method(Context c, string[] args) {
		Console.WriteLine("{0} ({1}): {2}", this, c, String.Join("; ", args));
	}
}

public class Context {
	public State State;
	private string _name;
	
	public Context(string name, State s) {
		this._name = name;
		this.State = s;
	}
	
	public Context(string name) : this(name, null) {
	}
	
	public override string ToString() {
		return this._name;
	}
	
	public void Method(string[] args) {
		if(this.State != null)
			this.State.Method(this, args);
	}
}