Iterators - in COBOL and C#

using System.Collections.Generic;

class Iterators
{
    static void Use()
    {
        foreach (int i in GetSequence())
        {
            System.Console.WriteLine(i);
        }

        var instance = new Iterators();
        foreach (int i in instance)
        {
            System.Console.WriteLine(i);
        }
    }

    static IEnumerable<int> GetSequence()
    {
        int c = 1;
        while (true)
        {
            c++;

            // yield the next number
            yield return c;

            if (c < 5)
            {
                // yield the next number
                yield return c * 10;
            }
            else
            {
                // end the iterator
                yield break;
            }
        }
    }

    // Define an iterator for the current class
    public IEnumerator<int> GetEnumerator()
    {
        for (int i = 23 ; i >= 0; i -= 5)
        {
            yield return i;
        }
    }
}

$set ilusing(System.Collections.Generic)

class-id Iterators.

method-id Use static.

    perform varying i as binary-long thru GetSequence()
        display i
    end-perform


    declare #instance = new Iterators()
    perform varying i as binary-long thru #instance
        display i
    end-perform
end method.


iterator-id GetSequence static yielding retn as binary-long.
    declare c as binary-long = 1
    perform until exit
        add 1 to c

        *> yield the next number
        set retn to c
        goback

        if c < 5
            *> yield the next number
            set retn to c * 10
            goback
        else
            *> end the iterator
            exit iterator
        end-if
    end-perform
end iterator.


*> Define an iterator for the current class
iterator-id self yielding retn as binary-long.
    perform varying i as binary-long from 23 by -5 until i < 0
        set retn to i
        goback
    end-perform
end iterator.
end class.

Imports System.Collections.Generic

class Iterators
    Shared Sub Use()
        For Each i In GetSequence()
            System.Console.WriteLine(i)
        Next
        Dim instance = new Iterators()
        For Each i In instance
            System.Console.WriteLine(i)
        Next
    End Sub

    Shared Iterator Function GetSequence() As IEnumerable(Of Integer)
        Dim c as Integer = 1
        while True
            c = c + 1
    
            ' yield the next number
            Yield c

            If (c < 5)
                ' yield the next number
                Yield c * 10
            Else
                ' end the iterator
                Exit Function
            End If
        End While
    End Function


    ' Define an iterator for the current class
    public Iterator Function GetEnumerator() As IEnumerator(Of Integer)
        For i = 23 To 0 Step -5
            Yield i
        Next
    End Function
End Class