Simple test of Enum.GetValues() with casting type and without

EnumGetValuesCastTest.md

Simple test of Enum.GetValues() with casting type and without

It was some time ago. I wondered why some people explicitly cast the type of value returned by the Enum.GetValues() function. I did some tests.

Unfortunately, the functions are so short that StopWatch is inaccurate. Therefore, I call them in a large loop and then divide the time by the number of repetitions.

public class C {
    enum Sizes
	{
	    Small,
    	Medium,
    	Large
	}
    void Fun1()
    {
        foreach (Sizes s in Enum.GetValues(typeof(Sizes)))
        {}
    }
    void Fun2()
    {
        foreach (Sizes s in (Sizes[])Enum.GetValues(typeof(Sizes)))
        {}
    }
}

static void Main(string[] args)
{
    C c = new C();
    int count = 1000000;
    do
    {
        Stopwatch watch = Stopwatch.StartNew();
        for (int i = 0; i < count; i++)
        { 
            c.Fun1();
            //c.Fun2();
        }
        watch.Stop();

        Console.WriteLine("Duration: {0:0.000} us",
                          watch.Elapsed.TotalMilliseconds * 1000 / count);
        
    } while (true);
}

I'm waiting a moment, until the results stabilize and then average the latter. Then I take the second function and run again. I've also done, a test of more values like. I don't remember what they were, but let's assume that 10, 100 and 1000.

The results are as follows:

Method	Enum elements	Mean	Faster than Fun1
Fun1	3	1.515 us
Fun2	3	1.019 us	1.49x
Fun1	10	3.998 us
Fun2	10	2.777 us	1.44x
Fun1	100	35.581 us
Fun2	100	21.056 us	1.69x
Fun1	1000	358.217 us
Fun2	1000	214.417 us	1.67x
			Mean: 1.5725x

That's why I wrote in a comment on stackoverflow.com that "my code run 1,6 times faster".

I know that this test was not perfect.

The continuation of this story will be... here