Question

There was a task to know which code is faster and why:

//A
        Stopwatch sw = new Stopwatch();
        Int32[] a = new Int32[10000000];
        int len = a.Length;
        sw.Start();
        //for (Int32 index = 0; index < len; index++)
        //{

        //    a[index] = 6;
        //}
        //sw.Stop();


//B
        for (Int32 index = 0; index < a.Length; index++)
        {

            a[index] = 6;
        }
        sw.Stop();

        var time = sw.ElapsedMilliseconds;

The avarage time of approach B is little more than A. Does anybody explain why?

Answer 1

My guess would be because you are polling the length of the array each time you loop, whereas the A approach only has to check a cached value of the length. So, ultimately, this comes down to the idea of caching