Csharp/CSharp Tutorial/Class/IEnumerable

IEnumerable<T>

using System;
using System.Collections.Generic;
public class Employee {
    public string Name;
    public string Title;
    public Employee(string name, string title) {
        Name = name;
        Title = title;
    }
    public override string ToString() {
        return string.Format("{0} ({1})", Name, Title);
    }
}
public class Team {
    private List<Employee> teamMembers = new List<Employee>();
    public IEnumerator<Employee> GetEnumerator() {
        foreach (Employee tm in teamMembers) {
            yield return tm;
        }
    }
    public IEnumerable<Employee> Reverse {
        get {
            for (int c = teamMembers.Count - 1; c >= 0; c--) {
                yield return teamMembers[c];
            }
        }
    }
    public IEnumerable<Employee> FirstTwo {
        get {
            int count = 0;
            foreach (Employee tm in teamMembers) {
                if (count >= 2) {
                    yield break;
                } else {
                    count++;
                    yield return tm;
                }
            }
        }
    }
    public void AddMember(Employee member) {
        teamMembers.Add(member);
    }
}
public class MainClass {
    public static void Main() {
        Team team = new Team();
        team.AddMember(new Employee("C", "C"));
        team.AddMember(new Employee("N", "K"));
        team.AddMember(new Employee("N", "S"));
        foreach (Employee member in team) {
            Console.WriteLine("  " + member.ToString());
        }
        foreach (Employee member in team.FirstTwo) {
            Console.WriteLine("  " + member.ToString());
        }
        foreach (Employee member in team.Reverse) {
            Console.WriteLine("  " + member.ToString());
        }
    }
}

Supporting foreach with IEnumerable and IEnumerator

using System;
using System.Collections;
   
class Rainbow : IEnumerable, IEnumerator
{
    private short IteratorIndex = -1;
   
    public IEnumerator GetEnumerator()
    {
        return this;
    }
   
    public object Current
    {
        get
        {
            switch(IteratorIndex)
            {
                case 0:
                    return "Red";
                case 1:
                    return "Orange";
                case 2:
                    return "Yellow";
                case 3:
                    return "Green";
                case 4:
                    return "Blue";
                case 5:
                    return "Indigo";
                case 6:
                    return "Violet";
                default:
                    return "*** ERROR ***";
            }
        }
    }
   
    public bool MoveNext()
    {
        IteratorIndex++;
        if(IteratorIndex == 7)
            return false;
        return true;
    }
   
    public void Reset()
    {
        IteratorIndex = -1;
    }
   
    public static void Main()
    {
        Rainbow MyRainbow = new Rainbow();
   
        foreach(string ColorName in MyRainbow)
            Console.WriteLine(ColorName);
    }
}