using System;

using System.Collections;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var generator = new OddGenerator();

        foreach(int odd in generator)

        {

            if(odd > 50) break;

            Console.WriteLine(odd);

        }

    }

}

​

// Note that IEnumerable<T> inherits IEnumerable and both have GetEnumerator() declaration.

public class OddGenerator : IEnumerable<int>

{

    public IEnumerator<int> GetEnumerator()

    {

        int i = 1;

        yield return i;

        while(true)

        {

            i += 2;

            yield return i;         

        }

    }

    // IEnumerable<T> inherits IEnumerable.

    // Due to conflicting signatures in IEnumearable and IEmumerable<T>,

    // we have to implement the method from the base IEnumerable interface.

    // Note: no access modifier in explicit implementation.

    IEnumerator IEnumerable.GetEnumerator()

    {

        // Actually this is not required for this demo.

        return this.GetEnumerator();

    }

}

​