Peter's Software House

using System;

using System.Collections.Generic;

namespace TestFilter

{

    static class Program

    {

        static void Main(string[] args)

        {

            // Add a whole bunch of names

            FilteredList list = new FilteredList();

            list.Add("Anne");

            list.Add("Brian");

            list.Add("Pieter");

            list.Add("Wayne");

            list.Add("Shane");

            list.Add("Susan");

            list.Add("Xavier");

            // There whould be 7

            Console.WriteLine(list.Count);

            // Use a public function to filter the list

            FilteredList filteredList = list.Filter(list.FilterFunction);

            //There should only be 2 stating with 'S'

            Console.WriteLine(filteredList.Count);

            foreach (string name in filteredList)

            {

                Console.WriteLine(name);

            }

            // Use one version of a lambda expression

            FilteredList filteredList2 = list.Filter(item => { return item.StartsWith("A"); });

            // Only one starting with 'A'

            Console.WriteLine(filteredList2.Count);

            foreach (string name in filteredList2)

            {

                Console.WriteLine(name);

            }

            // A better/shorter version of the previous lambda?  Definately cleaner

            FilteredList filteredList3 = list.Filter(item => item.StartsWith("Pi"));

            // Only one starting with 'Pi'

            Console.WriteLine(filteredList3.Count);

            foreach (string name in filteredList3)

            {

                Console.WriteLine(name);

            }

            Console.ReadLine();

        }

    }

    public class FilteredList : List<string>

    {

        public bool FilterFunction(string item)

        {

            return item.StartsWith("S");

        }

        public FilteredList Filter(Func<string, bool> condition)

        {

            FilteredList filteredList = new FilteredList();

            foreach (string item in this)

            {

                if (condition(item))

                {

                    filteredList.Add(item);

                }

            }

            return filteredList;

        }

    }

}

using System;

using System.Collections.Generic;

namespace TestMap

{

    static class Program

    {

        static void Main(string[] args)

        {

            VehicleList list = new VehicleList();

            list.Add(new GWiz());

            list.Add(new SmartCar());

            list.Add(new CityCar());

            list.Add(new PeopleMover());

            List<int> mappedList = list.Map(list, list.MapFunction);

            foreach (int numberOfSeats in mappedList)

            {

                Console.WriteLine(numberOfSeats);

            }

            Console.ReadLine();

        }

    }

    public class VehicleList : List<Vehicle>

    {

        public int MapFunction(Vehicle item)

        { 

            return item.NumberOfSeats;

        }

        public List<int> Map(VehicleList list, Func<Vehicle, int> mapFunction)

        {

            List<int> mappedList = new List<int>();

            foreach (Vehicle item in list)

            {

                mappedList.Add(mapFunction(item));

            }

            return mappedList;

        }

    }

    public abstract class Vehicle

    {

        public int NumberOfSeats { get; set; }

    }

    public class GWiz : Vehicle

    {

        public GWiz()

        {

            NumberOfSeats = 1;

        }

    }

    public class SmartCar : Vehicle

    {

        public SmartCar()

        {

            NumberOfSeats = 2;

        }

    }

    public class CityCar : Vehicle

    {

        public CityCar()

        {

            NumberOfSeats = 5;

        }

    }

    public class PeopleMover : Vehicle

    {

        public PeopleMover()

        {

            NumberOfSeats = 9;

        }

    }

}