gistfile1.txt

using System;
 2 					
 3 public class Program
 4 {
 5 	public static void Main()
 6 	{
 7 		CalculateClient client = new CalculateClient();
 8 		
 9 		client.SetCalculate(new Minus());
10    		Console.WriteLine("Minus: " + client.Calculate(7, 1));
11 
12 		client.SetCalculate(new Plus());	
13    		Console.WriteLine("Plus: " + client.Calculate(7, 1));
14 	}
15 }
16 
17 //The interface for the strategies
18 public interface ICalculate 
19 {  
20    int Calculate(int value1, int value2);
21 }
22 
23 //strategies
24 //Strategy 1: Minus
25 public class Minus : ICalculate 
26 {
27     public int Calculate(int value1, int value2) 
28     {
29         return value1 - value2;
30     }
31 }
32 
33 //Strategy 2: Plus
34 public class Plus : ICalculate 
35 {
36     public int Calculate(int value1, int value2) 
37     {
38         return value1 + value2;
39     }
40 }
41 
42 //The client
43 public class CalculateClient 
44 {
45     private ICalculate strategy;
46 
47     //Executes the strategy
48     public int Calculate(int value1, int value2) 
49     {
50         return strategy.Calculate(value1, value2);
51     }
52 	
53     //Change the strategy
54     public void SetCalculate(ICalculate strategy){
55         this.strategy = strategy;
56     }
57 }