Question

How can the yield return be refactored in .NET 4.0

public static void DoIt()
{
    foreach (int n in Power(2,4))
    {
        Console.Write(n);
    }
}


public static IEnumerable CalcPower(int base, int exponent)
{
    int res = 1;

    for (int c = 1; c <= high; counter++)
    {
        res = res * base;
        yield return result;
    }
}

Answer 1

Your approach is fine. That’s probably the way I’d implement it too. One change is that you should use the generic IEnumerable<int> instead of IEnumerable.

public static IEnumerable<int> Power(int baseNumber, int highExponent)

If you really want to do it another way, you can use LINQ, but in my opinion, it’s not as clear as the original code:

public static IEnumerable<int> Power(int baseNumber, int highExponent)
{
    return Enumerable.Range(1, highExponent)
        .Select(e => (int)Math.Pow(baseNumber, e));
}

The yield keyword has not been made obsolete. If the code is clearer with yield then use it.