What is Enumerables ?

Enumeration is in c#, also that is iteration in other languages. So, Enumeration is actually iteration.

A quick sample, following;

class Program
{
static void Main(string[] args)
{
Program p = new Program();
foreach(var c in p.GetCars())
{
Console.WriteLine(c);
}
Console.ReadLine();
}
IEnumerable<string> GetCars()
{
  yield return "BMW";
  yield return "Mercedes";
  yield return "Audi";
}
}

By debugging this example, you can see that the returns are coming one by one.