Strategy

// Strategy pattern -- Real World example

using System; using System.Collections; namespace DoFactory.GangOfFour.Strategy.RealWorld {       // MainApp test application    class MainApp   {      static void Main()     {        // Two contexts following different strategies       SortedList studentRecords = new SortedList();       studentRecords.Add("Samual");       studentRecords.Add("Jimmy");       studentRecords.Add("Sandra");       studentRecords.Add("Vivek");       studentRecords.Add("Anna");       studentRecords.SetSortStrategy( new QuickSort());       studentRecords.Sort();       studentRecords.SetSortStrategy( new ShellSort());       studentRecords.Sort();       studentRecords.SetSortStrategy( new MergeSort());       studentRecords.Sort();        // Wait for user       Console.Read();     }   }    // "Strategy"    abstract class SortStrategy   {      public abstract void Sort(ArrayList list);   }    // "ConcreteStrategy"    class QuickSort : SortStrategy   {      public override void Sort(ArrayList list)     {       list.Sort(); // Default is Quicksort       Console.WriteLine("QuickSorted list ");     }   }    // "ConcreteStrategy"    class ShellSort : SortStrategy   {      public override void Sort(ArrayList list)     {        //list.ShellSort(); not-implemented       Console.WriteLine("ShellSorted list ");     }   }    // "ConcreteStrategy"    class MergeSort : SortStrategy   {      public override void Sort(ArrayList list)     {        //list.MergeSort(); not-implemented       Console.WriteLine("MergeSorted list ");     }   }    // "Context"    class SortedList   {      private ArrayList list = new ArrayList();      private SortStrategy sortstrategy;      public void SetSortStrategy(SortStrategy sortstrategy)     {        this.sortstrategy = sortstrategy;     }      public void Add( string name)     {       list.Add(name);     }      public void Sort()     {       sortstrategy.Sort(list);        // Display results        foreach ( string name in list)       {         Console.WriteLine(" " + name);       }       Console.WriteLine();     }   } }