using System;using System.Collections.Generic;namespace ConsoleApplication8
{ class Program
{ static void Main(string[] args)
{
MusicTitles titles = new MusicTitles(); foreach (string title in titles)
{
Console.WriteLine(title);
}
Console.WriteLine(); foreach (string title in titles.Reverse())
{
Console.WriteLine(title);
}
Console.WriteLine(); foreach (string title in titles.Subset(2, 2))
{
Console.WriteLine(title);
Console.ReadLine();
}
}
} public class MusicTitles
{ string[] names = { "a", "b", "c", "d" }; public IEnumerator<string> GetEnumerator()
{ for (int i = 0; i < 4; i++)
{ yield return names[i];
}
} public IEnumerable<string> Reverse()
{ for (int i = 3; i >= 0; i--)
{ yield return names[i];
}
} public IEnumerable<string> Subset(int index, int length)
{ for (int i = index; i < index + length; i++)
{ yield return names[i];
}
}
}
}
