建设性和破坏性逆转的时机

我有一个家庭作业，我必须建设性地和破坏性地反转一个数组列表，并为列表的不同长度计时。我的数组列表更新每次我运行它，但它似乎没有在这些方法中注册，因为我没有得到我的时间值，似乎找不到我的错误。

到目前为止，我的代码如下:

public ArrayList ConstructiveReverseDeveloped()
    {            
        ArrayList Temp = new ArrayList();
        for (int i = Developed.Count - 1; i >= 0; i--)
        {
            Apps cur = (Apps)Developed[i];
            Temp.Add(cur);
        }
        return Temp;
    }
    public void TimingConstructive()
    {
        DateTime startTime;
        TimeSpan endTime;
        startTime = DateTime.Now;
        ConstructiveReverseDeveloped();
        endTime = DateTime.Now.Subtract(startTime);
        Console.WriteLine("---------------------------------------------------------");
        Console.WriteLine("Time taken for Constructive Reverse of Developed : {0}", endTime);
    }
public void DestructiveReverseDeveloped()
    {
        //ArrayList x = cloneDeveloped();
        for (int i = Developed.Count - 1; i >= 0; i--)
        {
            Apps cur = (Apps)Developed[i];
            Developed.RemoveAt(i);
            Developed.Add(cur);
        }
    }
    public void TimingDestructive()
    {
        DateTime startTime;
        TimeSpan endTime;
        startTime = DateTime.Now;
        DestructiveReverseDeveloped();
        endTime = DateTime.Now.Subtract(startTime);
        Console.WriteLine("Time taken for Destructive Reverse of Developed : {0}",endTime.ToString());
        Console.WriteLine("---------------------------------------------------------");
    }

你们能给我指出正确的方向，为什么我没有得到定时值?我不想要确切的答案，只想帮助理解。

谢谢

class Timer
{
    private DateTime startingTime;
    // stores starting time of code being tested
    private TimeSpan duration;
    // stores duration of code being tested
    public void startTime()
    {
        GC.Collect();   // force garbage collection
        GC.WaitForPendingFinalizers();
        /* wait until all heap contents finalizer methods have completed for removal of contents to be permanent */
        startingTime = DateTime.Now;
        // get current date/time
    }
    public void stopTime()
    {
        // .Subtract: TimeSpan subtraction
        duration = DateTime.Now.Subtract(startingTime);
    }
    public TimeSpan result()
    {
        return duration;
    }

}

public void TimingDestructive()
{
    Timer Time = new Timer();
    Time.startTime();
    DestructiveReverseDeveloped();
    Time.stopTime();
    Console.WriteLine("Time taken for Destructive Reverse of Developed : {0}ms",Time.result().TotalMilliseconds);
    Console.WriteLine("---------------------------------------------------------");