将 ETA 添加到嵌入式循环序列

Question

UPDATE 1:

Some of the solutions offered below seem good. However, I only know the amount of times a loop will iterate after it's parent loop's iterations have been determined. So I can't count all the iterations beforehand.

ORIGINAL QUESTION:

I have embedded loops in a program similar to this:

Prog1:

using System;
using System.Threading;

namespace time_remaining_loop_strip
{
    class Program
    {
        static void Main(string[] args)
        {
            var random = new Random();
            Console.Clear();

            // Simulate initiation delay
            Console.WriteLine("initiate");
            Thread.Sleep(random.Next(100, 1000));

            int intCount = random.Next(1, 10);

            for (int loop1 = 0; loop1 <= intCount; loop1++) 
            {
                // Simulate loop1 delay
                Console.WriteLine("\tloop1");
                Thread.Sleep(random.Next(100, 1000));

                for (int loop2 = 0; loop2 <= random.Next(1, 10); loop2++) 
                {
                    // Simulate loop2 delay
                    Console.WriteLine("\t\tloop2");
                    Thread.Sleep(random.Next(100, 1000));

                    for (int loop3 = 0; loop3 <= random.Next(1, 10); loop3++) 
                    {
                        // Simulate loop3 delay
                        Console.WriteLine("\t\t\tloop3");
                        Thread.Sleep(random.Next(100, 1000));

                        for (int loop4 = 0; loop4 <= random.Next(1, 10); loop4++) 
                        {
                            // Simulate loop4 delay
                            Console.WriteLine("\t\t\t\tloop4");
                            Thread.Sleep(random.Next(100, 1000));
                        }
                    }
                }
            }
        }
    }
}

I am trying to display Processing Time Remaining (ETA), so I can see a rough estimate of the amount of time remaining before the loop sequence above completes

I now have another bit of code which does display an ETA which works fine when the loop is very simplistic:

Prog2:

using System;
using System.Threading;

namespace time_remaining
{
    class Program
    {
        public static TimeSpan ComputeRemaining((int count, DateTime time) start, (int count, DateTime time) current, int end) =>
            current.count - start.count == 0
            ? TimeSpan.MaxValue
            : TimeSpan.FromSeconds((end - current.count) * current.time.Subtract(start.time).TotalSeconds / (current.count - start.count));

        static void Main(string[] args)
        {
            Console.Clear();

            var random = new Random();
            int Count = random.Next(10, 60);
            DateTime startTime = DateTime.Now;

            for (int i = 0; i <= Count; i++)
            {
                Thread.Sleep(random.Next(100, 2000));
                TimeSpan timeRemaining = ComputeRemaining((0, startTime), (i, DateTime.Now), Count);

                Console.SetCursorPosition(0,0);
                Console.Write("ETA: ");
                Console.Write(String.Format("{0} Days, {1} Hours, {2} Minutes, {3} Seconds", timeRemaining.Days.ToString().PadLeft(3,'0'), timeRemaining.Hours.ToString().PadLeft(2,'0'), timeRemaining.Minutes.ToString().PadLeft(2,'0'), timeRemaining.Seconds.ToString().PadLeft(2,'0')));
            }
        }
    }
}

When I try to combine the ETA aspect of Prog1 into Prog2, it does not seem to work well:

Prog3 = Prog1+Prog2:

using System;
using System.Threading;

namespace time_remaining_loop_strip
{
    class Program
    {
        public static TimeSpan ComputeRemaining((int count, DateTime time) start, (int count, DateTime time) current, int end) =>
            current.count - start.count == 0
            ? TimeSpan.MaxValue
            : TimeSpan.FromSeconds((end - current.count) * current.time.Subtract(start.time).TotalSeconds / (current.count - start.count));

        static void Main(string[] args)
        {
            DateTime startTime = DateTime.Now;
            
            var random = new Random();
            Console.Clear();

            // Simulate initiation delay
            //Console.WriteLine("initiate");
            Thread.Sleep(random.Next(100, 1000));

            int intCount = random.Next(1, 10);

            for (int loop1 = 0; loop1 <= intCount; loop1++) 
            {
                // Simulate loop1 delay
                //Console.WriteLine("\tloop1");
                Thread.Sleep(random.Next(100, 1000));

                for (int loop2 = 0; loop2 <= random.Next(1, 10); loop2++) 
                {
                    // Simulate loop2 delay
                    //Console.WriteLine("\t\tloop2");
                    Thread.Sleep(random.Next(100, 1000));

                    for (int loop3 = 0; loop3 <= random.Next(1, 10); loop3++) 
                    {
                        // Simulate loop3 delay
                        //Console.WriteLine("\t\t\tloop3");
                        Thread.Sleep(random.Next(100, 1000));

                        for (int loop4 = 0; loop4 <= random.Next(1, 10); loop4++) 
                        {
                            // Simulate loop4 delay
                            //Console.WriteLine("\t\t\t\tloop4");
                            Thread.Sleep(random.Next(100, 1000));
                        }
                    }
                }

                TimeSpan timeRemaining = ComputeRemaining((0, startTime), (loop1, DateTime.Now), intCount);

                Console.SetCursorPosition(0,0);
                Console.Write("ETA: ");
                Console.Write(String.Format("{0} Days, {1} Hours, {2} Minutes, {3} Seconds", timeRemaining.Days.ToString().PadLeft(3,'0'), timeRemaining.Hours.ToString().PadLeft(2,'0'), timeRemaining.Minutes.ToString().PadLeft(2,'0'), timeRemaining.Seconds.ToString().PadLeft(2,'0')));
            }
        }
    }
}

This doesn't seem to work very well at all. It does display an ETA, but it has long delays before it shows anything, because of the way the loop is structured.

How can I update this so the ETA code displays an ETA more accurately and at more predictive intervals, as in every second?

Answer 1

With the concession that you've just built a simple model of what's actually happening (you have some series of nested process of variable delay and count, which cannot even be determined until runtime), what you're asking for currently is a random number predictor.

There will be between n & m cycles (1 & 10 in your example) of between o & p duration (100 & 1000ms), but still random.. well, random quantized into bands. The way you've written it, this is dice-roll random (a dice has no memory), although in practice it seems more likely the duration of one cycle must somewhat imply the duration of the next, (which is how you've written ComputeRemaining ) and within one band the count of one loop must help with the count of the next.

So despite its apparent simplicity Prog2 covers our examples.. given a known loop count, where each cycle takes a random duration (which is in fact pick(n,m)^3*pick(o,p) .. but this is still just a random number) - predict the end. For reporting purposes, you'll want to refactor this to consider the inner loops as well too, but it's effectively the same process. ( ^3 is a simplification, it's actually a series of independent picks multiplied )

Ok, so we don't need to talk about time/delays (I mean.. you clearly want that, but it's just some number that represents the future - a TimeSpan is an long count of x ticks since some time... a finish time is just Now + x*tick ). So we can simplify this into a long predictor.

Setup

interface IAvger
{
    public double Avg { get; }
}
interface IAdder
{
    void Add(long value);
}
class Mean
{
    private int _count = 0;

    public double Total { get; private set; } = 0;
    public double? Avg => _count == 0 ? null : (double?)(Total / _count);

    public void Add(double val)
    {
        Total += val;
        _count++;
    }
}

You can ignore the interfaces (I used them when switching out potential solutions). Class Mean should be familiar... it calculates the mean average of a number of values, scaling/adapting as more values are found.

/// <summary>
/// Equivalent to your ComputeRemaining
/// </summary>
class RunningAvg : IAvger, IAdder
{
    private Mean _mean = new Mean();
    private readonly double _guess;
    public RunningAvg(double guess)
    {
        _guess = guess;
    }

    public double Avg => _mean.Avg ?? _guess;

    public void Add(long value) => _mean.Add(value);
}

Here's an equivalent to your ComputeRemaining . The value of guess helps an early prediction when nothing else is known (vs the equivalent of TimeSpan.Max )

/// <summary>
/// Drop the lowest and highest value
/// - Fairly typical in stats, however note this is only one biggest/smallest
/// (will work best when the standard devation is low, and outliers
/// are rare)
/// </summary>
class IgnoreExtremes : IAvger, IAdder
{
    private long? _worst;
    private long? _best;
    private Mean _mean = new Mean();
    private readonly int _wt;
    private readonly double _guess;
    public IgnoreExtremes(double guess, int weight = 4)
    {
        _wt = weight;
        _guess = guess;
    }

    public long Best => _best ?? (long)Math.Round(_guess);
    public long Worst => _worst ?? (long)Math.Round(_guess);

    public double Avg
    {
        get
        {
            var avg = _mean.Avg;
            if (!avg.HasValue) return _guess;
            return (Best + _wt * avg.Value + Worst) / (2 + _wt);
        }
    }

    public void Add(long value)
    {
        if (!_best.HasValue)
        {
            _best = value;
        }
        else if (value < _best)
        {
            _mean.Add(_best.Value);
            _best = value;
        }
        else if (!_worst.HasValue)
        {
            _worst = value;
        }
        else if (value > _worst)
        {
            _mean.Add(_worst.Value);
            _worst = value;
        }
        else
        {
            _mean.Add(value);
        }
    }
}

Finally some stats! IgnoreExtremes suppresses the highest and lowest (single) value. In scientific sampling it's fairly typical to ignore these, however with a real random distribution of numbers (eg dice roll, or random.Next ) only one extreme will be discarded. This should predict better numbers than RunningAvg . Note this is a form of weighted average, you can tune it (slightly) by supplying a weight value at construction ( wt=4 is fairly common), or tying _wt to _mean.count (some code changes required)

class IgnoreStdDevOutlier : IAvger, IAdder
{
    private const int AT_LEAST = 5;
    private Mean _mean = new Mean();
    private readonly List<long> _vals = new List<long>();
    private readonly double _guess;
    //private long _tot;
    private readonly double _outlierStdDevMulti;
    public IgnoreStdDevOutlier(double guess, double outlierStdDevMulti = 2)
    {
        _guess = guess;
        _outlierStdDevMulti = outlierStdDevMulti;
    }

    private double StdDev()
    {
        var avg = Avg;
        double tot = 0;
        foreach (var item in _vals)
            tot += (item - avg) * (item - avg);
        return Math.Sqrt(tot / (_vals.Count - 1));
    }

    public void Add(long value)
    {
        _vals.Add(value);
        if (_vals.Count > AT_LEAST)
        {
            var avg = Avg;
            var sd = StdDev();
            var min = avg - _outlierStdDevMulti * sd;
            var max = avg + _outlierStdDevMulti * sd;
            //Ignore outliers
            if (value < min || value > max) return;
        }
        _mean.Add(value);
    }

    public double Avg => _mean.Avg ?? 0;
}

Another statistics approach is to ignore values more than n*StandardDeviation from average, where n is often 2 or 3 (you'll find conflicting opinions). All values seen are part of the standard deviation, but only those that aren't outliers are considered part of the average. This ends up acting like a suppression factor, preventing the estimate swinging too much.

Alright, so to run a test we need some sort of measuring class:

class Performance
{
    private readonly List<long> _set = new List<long>();
    private long _actual;

    public void Add(long item) => _set.Add(item);

    public void SetFinal(long final) => _actual = final;

    public void Report()
    {
        foreach (var item in _set)
        {
            Console.WriteLine("{0} {1} = {2}", item, _actual, (item / (double)_actual - 1) * 100);
        }
    }
}

A real guess can't know the final ( _actual ) value, but this class allows us to see how the guess is doing so far.

Finally the program class:

class Program
{
    const int MIN_MSEC = 100;
    const int MAX_MSEC = 1000;
    const int MIN_LOOP = 10;
    const int MAX_LOOP = 50;

    static void C(Random random)
    {
        int nm = random.Next(MAX_LOOP, MAX_LOOP);
        var guess = (double)((MAX_LOOP + MIN_LOOP) / 2 * (MAX_MSEC + MIN_MSEC) / 2);

        var predict = new RunningAvg(guess);
        //var predict = new IgnoreExtremes(guess);
        //var predict = new IgnoreStdDevOutlier(guess,3);
        var per = new Performance();
        long tot = 0;
        for (int i = 0; i <= nm; i++)
        {
            var op = random.Next(MIN_MSEC, MAX_MSEC);
            predict.Add(op);
            per.Add((long)Math.Round(predict.Avg * nm));
            tot += op;
        }
        per.SetFinal(tot);
        per.Report();
    }

    static void Main(string[] args)
    {
        var random = new Random();
        C(random);
    }
}

You can ignore the work is done in a method called C (just a side effect of the code - A was your Prog1, while B was Prog2). Within C try changing which of RunningAvg , IgnoreExtremes or IgnoreStdDevOutlier is uncommented. Because, again, what's written is dice-roll random, you cannot take a single run as a good benchmark. The next stage is to wrap this in repeat-runs and take the average of the standard deviation of the predictions (or perhaps only the late predictions - a user probably doesn't mind if an early estimate is far off, as long as by the end it isn't jumping around) - but I ran out of time. I find IgnoreStdDevOutlier , on average, converges on the right answer fairly swiftly being off by 0-1% by the end. IgnoreExtremes suffers from only ignoring one extreme (in each direction), so it's sort of a light version of IgnoreStdDevOutlier . If your data isn't random, and there are only occasionally extreme cases - it'll do just fine. RunningAvg doesn't actually perform terribly some of the time, other times it's off by double digit percentages all the way through. Random numbers, if only they were easy to predict.

Note on usage

• Timespan.Ticks is a long. All of this is written to predict a long, which can be considered the difference between then and now. To directly switch use new Timespan(long ticks) to build the spans, and DateTime.Now.Subtract(startTime).Ticks to get a long from a span. Obviously all these classes could be re-written for TimeSpan instead of long .. unfortunately there isn't an easy generic where constraint that includes both long and TimeSpan

Answer 2

You can know how many times(t) loop 4 (L4) will execute multiplying L1t L2t L3t*L4t = total. Now at the very beginning you declare

dt = DateTime.Now;
count = 0L;

Now inside L4 you increase count and calculates how much time is elapsed

et= DateTime.Now - dt;
count++;

And there using rule of three you calculate how many seconds are left to reach the total iterations.

remainingSeconds = (total*et.TotalSeconds/count) - et.TotalSeconds;

Now the ETA is

DateTime.Now.AddSeconds(remainingSeconds);

Answer 3

I used below logic to solve this.

1. Before first foreach each loop I calculated the all different loops count.

2. After that I created 4 different variables to hold sleep time for each loop which is settings inside them.

3. Now before first for loop I calculated the total time in milliseconds that will be taken be all loops using below logic:

   var totalTime = (firstLoopCount * firstLoopSleepTime) + (firstLoopCount * secondLoopCount * secondLoopSleepTime) + (firstLoopCount * secondLoopCount * thirdLoopCount * thirdLoopSleepTime) + (firstLoopCount * secondLoopCount * thirdLoopCount * fourthLoopCount * fourthLoopSleepTime);

Note : I added 1 in function call (GetTotoalTimeinMilliSecond) where loops count is passing because loop is starting from 0 and ending with different loops count including itself.

4. Now before loop start, printed total time taken
5. Inside each loop, after thread sleep, subtract thread sleep time from total time and print that. And set new calculated time as total time.
6. Repeat this inside every loop.

Below is the code:

 class Program
 {

    static void Main(string[] args)
    {
        DateTime startTime = DateTime.Now;

        var random = new Random();
        Console.Clear();

        // Simulate initiation delay
        //Console.WriteLine("initiate");
        Thread.Sleep(random.Next(100, 1000));

        int firstLoopCount =  random.Next(1, 10);
        int secondLoopCount = random.Next(1, 10);
        int thirdLoopCount = random.Next(1, 10);
        int fourthLoopCount = random.Next(1, 10);

        int firstLoopSleepTime = random.Next(100, 1000);
        int secondLoopSleepTime =random.Next(100, 1000);
        int thirdLoopSleepTime = random.Next(100, 1000);
        int fourthLoopSleepTime = random.Next(100, 1000);
        //**************Added 1 because loop is starting from 0 and ending with different loops count including itself.
        var totalTimeinMillSec = GetTotoalTimeinMilliSecond(firstLoopCount + 1, secondLoopCount + 1, thirdLoopCount + 1, fourthLoopCount + 1, firstLoopSleepTime, secondLoopSleepTime, thirdLoopSleepTime, fourthLoopSleepTime);

        PrintAndGetTimeRemaining(totalTimeinMillSec);        
        for (int loop1 = 0; loop1 <= firstLoopCount; loop1++)
        {
            // Simulate loop1 delay
            //Console.WriteLine("\tloop1");

            Thread.Sleep(firstLoopSleepTime);
            totalTimeinMillSec = PrintAndGetTimeRemaining(totalTimeinMillSec - firstLoopSleepTime);
            
            for (int loop2 = 0; loop2 <= secondLoopCount; loop2++)
            {
                // Simulate loop2 delay
                //Console.WriteLine("\t\tloop2");
                Thread.Sleep(secondLoopSleepTime);                   
                totalTimeinMillSec = PrintAndGetTimeRemaining(totalTimeinMillSec - secondLoopSleepTime);
                for (int loop3 = 0; loop3 <= thirdLoopCount; loop3++)
                {
                    // Simulate loop3 delay
                    //Console.WriteLine("\t\t\tloop3");
                    Thread.Sleep(thirdLoopSleepTime);                      
                    totalTimeinMillSec = PrintAndGetTimeRemaining(totalTimeinMillSec - thirdLoopSleepTime);
                    for (int loop4 = 0; loop4 <= fourthLoopCount; loop4++)
                    {
                        // Simulate loop4 delay
                        //Console.WriteLine("\t\t\t\tloop4");
                        Thread.Sleep(fourthLoopSleepTime);                           
                        totalTimeinMillSec = PrintAndGetTimeRemaining(totalTimeinMillSec - fourthLoopSleepTime);
                    }
                }
            }
        }
    }

    private static int PrintAndGetTimeRemaining(int totalTimeinMillSec)
    {
        TimeSpan timeRemaining = TimeSpan.FromMilliseconds(totalTimeinMillSec);

        Console.SetCursorPosition(0, 0);
        Console.WriteLine("ETA: ");
        Console.WriteLine(String.Format("{0} Days, {1} Hours, {2} Minutes, {3} Seconds, {4} Milliseconds", timeRemaining.Days.ToString().PadLeft(3, '0'), timeRemaining.Hours.ToString().PadLeft(2, '0'), timeRemaining.Minutes.ToString().PadLeft(2, '0'), timeRemaining.Seconds.ToString().PadLeft(2, '0'), timeRemaining.Milliseconds.ToString().PadLeft(2, '0')));
        return totalTimeinMillSec;
    }

    private static int GetTotoalTimeinMilliSecond(int firstLoopCount, int secondLoopCount, int thirdLoopCount, int fourthLoopCount, int firstLoopSleepTime, int secondLoopSleepTime, int thirdLoopSleepTime, int fourthLoopSleepTime)
    {
        var totalTime = (firstLoopCount * firstLoopSleepTime +
                                  firstLoopCount * secondLoopCount * secondLoopSleepTime +
                                  firstLoopCount * secondLoopCount * thirdLoopCount * thirdLoopSleepTime +
                                  firstLoopCount * secondLoopCount * thirdLoopCount * fourthLoopCount * fourthLoopSleepTime);
        
        return totalTime;
    }

}


}

Please let me know If I missed something.

Answer 4

I think this may work for you; in order to accomplish the solution I created a few classs to help.

The code itself has some comments.

First an enum, to know in which loop we are; it is not fully necessary, but it can be worth for a refactor later on.

public enum LoopEnum
{
    loop1,
    loop2,
    loop3,
    loop4
}

Then i created a class called EtaLoop which will contain the entire loop information/logic to know how long a single iteration of a loop takes, I use StopWatch :

public class EtaLoop
{
    public readonly int TotalIterations;
    private readonly List<long> _loopsTimesInMiliseconds;
    private readonly Stopwatch _stopwatch;

    public EtaLoop(int totalIterations)
    {
        //+1 as the loops starts on 0
        TotalIterations = totalIterations+1;
        _loopsTimesInMiliseconds = new List<long>();
        _stopwatch = new Stopwatch();

    }
    public double AvgExecution()
    {
        return _loopsTimesInMiliseconds.Any() ? _loopsTimesInMiliseconds.Average(a => a) : 0;
    }

    public void Start()
    {
        if(!_stopwatch.IsRunning)
            _stopwatch.Start();
    }

    public void Stop()
    {
        _stopwatch.Stop();
        _loopsTimesInMiliseconds.Add(_stopwatch.ElapsedMilliseconds);
        ResetStopWatch();
    }
    public int CurrentIteration()
    {
        return _loopsTimesInMiliseconds.Count();
    }

    public long EstimatedCurrentIteration()
    {
        return Convert.ToInt64(_loopsTimesInMiliseconds.Average(a => a) * TotalIterations);
    }

    private void ResetStopWatch()
    {
        _stopwatch.Reset();
    }
}

the methods I think are clear enough without more explanation.

another class called EtaTime which will contain more logic, this class is a wrapper for EtaLoop for example, if a for has 5 iterations, it will contain 5 elements on the list.

each element ( EtaLoop ) is added to the list, once we finish (all the iterations are finished) It has some more methods, one of them, the "hard one" it is explained

public class EtaTime
{
    public readonly List<EtaLoop> Loops;
    public readonly LoopEnum Loop;
    private EtaLoop _currentLoop;

    public EtaTime(LoopEnum loop)
    {
        Loops = new List<EtaLoop>();
        Loop = loop;
    }

    public void SetUpTotal(int totalIterations)
    {
        _currentLoop = new EtaLoop(totalIterations);
    }

    public void StartLoop()
    {
        _currentLoop.Start();

    }

    public void EndLoop()
    {
        _currentLoop.Stop();
    }

    public void RegisterLoop()
    {
        Loops.Add(_currentLoop);
    }

    /// <summary>
    /// Get the average time per execution, and the average number of loops per parent loop.
    /// The idea is to know how many times (and how long) the loop x is executed per each x-1
    /// </summary>
    /// <returns></returns>
    public (double, double) GetAvgTimeAndAvgExTimes()
    {
        double avgTimePerLoop = Loops.Any() ? Loops.Average(a => a.AvgExecution()) : _currentLoop.AvgExecution();
        double avgTotalLoopsIteration = Loops.Any() ? Loops.Average(a => a.TotalIterations) : _currentLoop.TotalIterations;
        return (avgTimePerLoop, avgTotalLoopsIteration);
    }

    public int GetCurrentIteration()
    {
        return _currentLoop.CurrentIteration();
    }

    public int TotalIterations()
    {
        return _currentLoop.TotalIterations;
    }
}

Finally the wrapper for the EtaTimeHelper which will contain all the EtaTimes ; originally i was thinking to make a list, thats why the enum was for, but, i think like this is more clear. Note: this class can be split/moved to extension methods.

The main points here are RegisterLoop every time we finish a loop we have to call that method; and it needs to be here because i need the information from the other loops.

public class EtaTimeHelper
{
    //This part can be done in a list, but i think it is easier to see like this.
    public readonly EtaTime Loop1;
    public readonly EtaTime Loop2;
    public readonly EtaTime Loop3;
    public readonly EtaTime Loop4;
    public readonly DateTime StartTime;
    private DateTime _lastPrintTime;
    private const int TimeBetweenPrintsInSeconds = 10;


    public EtaTimeHelper()
    {
        Loop1 = new EtaTime(LoopEnum.loop1);
        Loop2 = new EtaTime(LoopEnum.loop2);
        Loop3 = new EtaTime(LoopEnum.loop3);
        Loop4 = new EtaTime(LoopEnum.loop4);
        StartTime = DateTime.Now;
        _lastPrintTime = DateTime.MinValue;
    }

    public void RegisterLoop(LoopEnum loopNumber)
    {

        switch (loopNumber)
        {
            case LoopEnum.loop1:
                Loop1.RegisterLoop();
                break;
            case LoopEnum.loop2:
                Loop2.RegisterLoop();
                break;
            case LoopEnum.loop3:
                Loop3.RegisterLoop();
                break;
            case LoopEnum.loop4:
                Loop4.RegisterLoop();
                break;
            default:
                throw new NotImplementedException("please register the loop");

        }

        PrintCompletionTime(DateTime.Now, loopNumber);
    }


    public void PrintCompletionTime(DateTime printTime, LoopEnum loopNumber)
    {
        if(_lastPrintTime.AddSeconds(TimeBetweenPrintsInSeconds) < printTime)
        {
            var time = CalculatePredictionTime(loopNumber);
            Print(time);
            _lastPrintTime = printTime;
        }
    }

    private long CalculatePredictionTime(LoopEnum loopNumber)
    {
        switch (loopNumber)
        {
            case LoopEnum.loop1: 
                return LoopPrediction(Loop1.GetAvgTimeAndAvgExTimes());
            case LoopEnum.loop2:
                return Loop2Prediction(Loop1, Loop2);
            case LoopEnum.loop3:
                return Loop3Prediction(Loop1, Loop2, Loop3);
            case LoopEnum.loop4:
                return Loop4Prediction(Loop1, Loop2, Loop3, Loop4);
            default:
                throw new NotImplementedException("please register the loop");

        }


        //If all loops in #1 are finished, all sub loops are also finished. which means, it is the "end of the loop"
        long LoopPrediction((double, double) avgTimeAndAvgExTimes)
        {
            double avgTimePerLoop = avgTimeAndAvgExTimes.Item1;
            double avgIterations = avgTimeAndAvgExTimes.Item2;
            return Convert.ToInt64(avgTimePerLoop * avgIterations);
        }

        long Loop2Prediction(EtaTime loop1, EtaTime loop2)
        {
            
            var loop1Prediction = LoopPrediction(loop1.GetAvgTimeAndAvgExTimes());

            var loop2Values = loop2.GetAvgTimeAndAvgExTimes();
            long avgPerLoop = LoopPrediction(loop2Values);

            var loop1AvgIterations = loop1.GetAvgTimeAndAvgExTimes().Item2;
            var expectedLoop2Iterations = loop1AvgIterations;

            double loop2Predictions = avgPerLoop * expectedLoop2Iterations;

            if (loop1Prediction == 0)
            {
                return Convert.ToInt64(loop2Predictions);
            }
            else
            {
                //1+current iteration
                return loop1Prediction + loop2.GetCurrentIteration();
            }
        }

        long Loop3Prediction(EtaTime loop1, EtaTime loop2, EtaTime loop3)
        {
            var loop1_2Prediction = Loop2Prediction(loop1, loop2);

            var loop3Values = loop3.GetAvgTimeAndAvgExTimes();
            long avgPerLoop = LoopPrediction(loop3Values);

            var loop2AvgIterations = loop2.GetAvgTimeAndAvgExTimes().Item2;
            var loop1AvgIterations = loop1.GetAvgTimeAndAvgExTimes().Item2;
            var expectedLoop3Iterations = loop2AvgIterations * loop1AvgIterations;

            double loop3Predictions = avgPerLoop * expectedLoop3Iterations;

            if (loop1_2Prediction == 0)
            {
                return Convert.ToInt64(loop3Predictions);
            }
            else
            {
                //1-2+current iteration
                return loop1_2Prediction+ loop3.GetCurrentIteration();
            }
        }

        long Loop4Prediction(EtaTime loop1, EtaTime loop2, EtaTime loop3, EtaTime loop4)
        {
            var loop1_2_3Prediction = Loop3Prediction(loop1, loop2, loop3);

            var loop4Values = loop4.GetAvgTimeAndAvgExTimes();
            long avgPerLoop = LoopPrediction(loop4Values);

            var loop2AvgIterations = loop2.GetAvgTimeAndAvgExTimes().Item2;
            var loop1AvgIterations = loop1.GetAvgTimeAndAvgExTimes().Item2;
            var loop3AvgIterations = loop3.GetAvgTimeAndAvgExTimes().Item2;
            var expectedLoop4Iterations = loop2AvgIterations * loop1AvgIterations* loop3AvgIterations;

            double loop4Predictions = avgPerLoop * expectedLoop4Iterations;

            if (loop1_2_3Prediction == 0)
            {
                return Convert.ToInt64(loop4Predictions);
            }
            else
            {
                //1-2-3+current iteration
                return loop1_2_3Prediction + loop4.GetCurrentIteration();
            }
        }
    }

    private void Print(long ms)
    {
        DateTime estimatedCompletionTime = StartTime.AddMilliseconds(ms);

        TimeSpan leftTime = (estimatedCompletionTime - DateTime.Now);

        Console.WriteLine("ETA: ");
        Console.WriteLine($"{leftTime.Days} Days, {leftTime.Hours} Hours, {leftTime.Minutes} Minutes, {leftTime.Seconds} Seconds");//, leftTime.Days.ToString().PadLeft(3, '0'), leftTime.Hours.ToString().PadLeft(2, '0'), leftTime.Minutes.ToString().PadLeft(2, '0'), leftTime.Seconds.ToString().PadLeft(2, '0')));
        Console.WriteLine($"on {estimatedCompletionTime.ToString("yyyy/MM/dd HH:mm:ss")}");
        Console.WriteLine($"Current Time: {DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss")}");
    }

}

and the print. as you mention you want some mecanisim to print, but you did not specify if it is a consol app a web or a winforms app. Probably it is winforms if it is a desktop app you probably can do something like myLabel.SetPropertyThreadSafe to modify the label you want to update. The algorithim which calculates the time it is on CalculatePredictionTime I tried to make it a single method for n number of loops but I couldnt.

Now the main.

I did a few changes on the Thread.Sleep as it is easier for me to figure it out if makes sense while i was testing. also, a range 10-100 (10x) I thought it was very big, i reduced it for testing reasons.

the code follows a pattern, first you need to instanciate the EtaTimeHelper class.

• before each loop you have to setUpTotal which means you have to pass the number of iterations are going to be.
• The first line of the loop will be .StartLoop() this will start the StopWatch and the last line of the loop (before the } ) will be a .EndLoop() ;
• after the closing bracket } you have to indicate the etaTimeHelper.RegisterLoop(loopNumber); passing as parameter the loop number this will print if necessary the time.

static void Main(string[] args)
{

    var random = new Random();
    Console.Clear();

    // Simulate initiation delay
    //Console.WriteLine("initiate");

    EtaTimeHelper etaTimeHelper = new EtaTimeHelper();


    int intCount = random.Next(1, 10);
    etaTimeHelper.Loop1.SetUpTotal(intCount);
    for (int loop1 = 0; loop1 <= intCount; loop1++)
    {
        etaTimeHelper.Loop1.StartLoop();

        // Simulate loop1 delay
        Console.WriteLine("\tloop1");
        Thread.Sleep(random.Next(40, 50));

        //number of times the loop 2 is going to execute inside this loop 1;
        int loop2times = random.Next(1, 10);
        etaTimeHelper.Loop2.SetUpTotal(loop2times);
        for (int loop2 = 0; loop2 <= loop2times; loop2++)
        {
            etaTimeHelper.Loop2.StartLoop();

            // Simulate loop2 delay
            //Console.WriteLine("\t\tloop2");
            Thread.Sleep(random.Next(30, 40));
            
            //number of times the loop 3 is going to execute inside this loop 3;
            int loop3times = random.Next(1, 10);
            etaTimeHelper.Loop3.SetUpTotal(loop3times);
            for (int loop3 = 0; loop3 <= loop3times; loop3++)
            {
                etaTimeHelper.Loop3.StartLoop();

                // Simulate loop3 delay
                //Console.WriteLine("\t\t\tloop3");
                Thread.Sleep(random.Next(10, 20));


                var loop4Times = random.Next(1, 10);
                etaTimeHelper.Loop4.SetUpTotal(loop4Times);
                for (int loop4 = 0; loop4 <= loop4Times; loop4++)
                {
                    etaTimeHelper.Loop4.StartLoop();
                    // Simulate loop4 delay
                    //Console.WriteLine("\t\t\t\tloop4");
                    Thread.Sleep(random.Next(20, 30));

                    etaTimeHelper.Loop4.EndLoop();
                }
                etaTimeHelper.RegisterLoop(LoopEnum.loop4);
                etaTimeHelper.Loop3.EndLoop();
            }
            etaTimeHelper.RegisterLoop(LoopEnum.loop3);
            etaTimeHelper.Loop2.EndLoop();
        }
        etaTimeHelper.RegisterLoop(LoopEnum.loop2);
        etaTimeHelper.Loop1.EndLoop();
    }
    etaTimeHelper.RegisterLoop(LoopEnum.loop1);
}

Here is a "working" fiddle https://dotnetfiddle.net/Z06W4g note: it times out after a few seconds, in your local machine works fine.

Answer 5

In order to assert the ETA every second, what I have done is attaching an event to a System.Timers.Timer object. The event will be triggered every second in order to continuously providing the user with the ETA feedback.

            System.Timers.Timer aTimer = new System.Timers.Timer(1000);
            aTimer.Elapsed += (sender, e) => ATimer_Elapsed(sender, e, new MyEventArguments
            {
                Loop1TotalIterations = intCount,
                CurrentIndex = loop1,
                Start = startTime

            });
            aTimer.AutoReset = true;
            aTimer.Enabled = true;

In your example we are using the Thread.Sleep in order simulate a delay.

Using Thread.Sleep will put everything to sleep - therefor the time logic will be inaccurate.

What I have done is creating a Multi-thread application - in order to run the logic on one thread and the time on another. Therefor when we pause the time checking and ETA will continue to run.

Putting it all together we have the following:

namespace ConsoleApp10
{
    #region Usings

    using System;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Timers;

    #endregion

    /// <summary>
    /// Event class to be passed to ElapsedEventHandler
    /// </summary>
    public class MyEventArguments
    {
        public int Loop1TotalIterations { get; set; }

        public DateTime Start { get; set; }

        public DateTime CurrentDate => DateTime.Now;

        public int CurrentIndex { get; set; }
    }

    class Program
    {
        /// <summary>
        ///  Compute the remaining time
        /// </summary>
        public static void ComputeRemaining((int count, DateTime time) start, (int count, DateTime time) current, int end)
        {
            var T = current.count - start.count == 0
                ? TimeSpan.MaxValue
                : TimeSpan.FromSeconds((end - current.count) * current.time.Subtract(start.time).TotalSeconds / (current.count - start.count));

            Console.Clear();
            Console.SetCursorPosition(0, 0);
            Console.ForegroundColor = (ConsoleColor)15;
            Console.WriteLine(String.Format("ETA: {0} Days, {1} Hours, {2} Minutes, {3} Seconds",
                T.Days.ToString().PadLeft(3, '0'),
                T.Hours.ToString().PadLeft(2, '0'),
                T.Minutes.ToString().PadLeft(2, '0'),
                T.Seconds.ToString().PadLeft(2, '0')));

            Console.WriteLine();
        }
        
        static void Main(string[] args)
        {
            DateTime startTime = DateTime.Now;
            Random random = new Random();
            int intCount = random.Next(1, 10);
            int loop1 = 0;

            var time = Task.Factory.StartNew(() =>
            {
                System.Timers.Timer aTimer = new System.Timers.Timer(1000);
                aTimer.Elapsed += (sender, e) => ATimer_Elapsed(sender, e, new MyEventArguments
                {
                    Loop1TotalIterations = intCount,
                    CurrentIndex = loop1,
                    Start = startTime

                });
                aTimer.AutoReset = true;
                aTimer.Enabled = true;

            });

            var logic = Task.Factory.StartNew(() =>
            {
                PrintAndSimulate("Initiate");

                for (loop1 = 0; loop1 <= intCount; loop1++)
                {
                    PrintAndSimulate("\tloop1");

                    for (int loop2 = 0; loop2 <= random.Next(1, 10); loop2++)
                    {
                        PrintAndSimulate("\t\tloop2");

                        for (int loop3 = 0; loop3 <= random.Next(1, 10); loop3++)
                        {
                            PrintAndSimulate("\t\t\tloop3");

                            for (int loop4 = 0; loop4 <= random.Next(1, 10); loop4++)
                            {
                                PrintAndSimulate("\t\t\t\tloop4");
                            }
                        }
                    }
                }
            });

            Task.WaitAll(new[] { time, logic });
        }

        /// <summary>
        ///  Display the info string and simulates a delay
        /// </summary>
        private static void PrintAndSimulate(string info)
        {
            int time = new Random().Next(100, 1000);
            Console.SetCursorPosition(5, 5);
            Console.ForegroundColor = (ConsoleColor)new Random().Next(15);
            Console.WriteLine(info);
            Thread.Sleep(time);
        }

        /// <summary>
        /// ElapsedEventHandler
        /// </summary>
        private static void ATimer_Elapsed(object sender, ElapsedEventArgs e, MyEventArguments myEventArguments)
        {
            ComputeRemaining((0, myEventArguments.Start), (myEventArguments.CurrentIndex, myEventArguments.CurrentDate), myEventArguments.Loop1TotalIterations);
        }
    }
}

I have added some colours to the console feedback - making a change more evident.

Answer 6

I think you will have to benchmark it a few times for the operation that you need and then extrapolate. There are variables here. The compute power and storage type (if involved) and network (if involved) of the target will all contribute to the ETA and every execution will have a different execution time. But ETA can be closely predicted after some benchmarking. And if you want to be really clever, you can show a warning that it may take more time than the displayed ETA because of x, y and z eg CPU utilisation by other processes running on the target.

Jon Skeet is an authority on this topic and he has a good resource here: link

Also read here for how the types in your operation and bitness of the CPU will affect your ETA: link

Answer 7

This may not be ideal solution but has potential to solve the issue.
First you build a Tree of Action containing what you are going to execute and then execute the Actions by iterating the tree.
The tree acts as index of what you are going to execute. Even you can track what is being executed. Whats done and whats pending.

I have nested the actions in single level in the tree for demo purpose but you can nest the tree as much as possible, inside loops etc.(pseudo code ahead but poc builds and executes well)

class Program
{
    static void Main(string[] args)
    {
        var random = new Random();

        TreeNode<Action> root = new TreeNode<Action>(() => { });

        var loop1 = root.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        var loop2 = loop1.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        var loop3 = loop2.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        var loop4 = loop3.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        var loop5 = loop4.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        var loop6 = loop5.AddChild(() =>
        {
            int Count = random.Next(1, 3);

            for (int i = 0; i <= Count; i++)
                Thread.Sleep(random.Next(100, 2000));
        });

        root.Execute(DateTime.Now);
        Console.ReadLine();
    }
}
public static class Extensions
{
    public static string Humanize(this TimeSpan timeRemaining)
    {
        return String.Format("{0} Days, {1} Hours, {2} Minutes, {3} Seconds", timeRemaining.Days.ToString().PadLeft(3, '0'), timeRemaining.Hours.ToString().PadLeft(2, '0'), timeRemaining.Minutes.ToString().PadLeft(2, '0'), timeRemaining.Seconds.ToString().PadLeft(2, '0'));
    }

    public static void PrintETA(this TimeSpan timeRemaining)
    {
        //Console.SetCursorPosition(0, 0);
        Console.Write("ETA: ");
        Console.Write(timeRemaining.Humanize());
    }

    public static TimeSpan ComputeRemaining((int count, DateTime time) start, (int count, DateTime time) current, int end) =>
        current.count - start.count == 0
        ? TimeSpan.MaxValue
        : TimeSpan.FromSeconds((end - current.count) * current.time.Subtract(start.time).TotalSeconds / (current.count - start.count));

    public static void Execute(this TreeNode<Action> root, DateTime startTime)
    {
        var current = root;
        var end = current.Count();
        var currentCount = 1;
    Iterate:
        var Count = current.Children.Count();
        for (int i = 0; i < Count; i++)
        {
            TreeNode<Action> node = current.Children.ElementAt(i);
            node.Data();

            TimeSpan timeRemaining = ComputeRemaining((0, startTime), (currentCount++, DateTime.Now), end-1);
            timeRemaining.PrintETA();
            Console.WriteLine();
            Console.WriteLine("Processed {0} of {1}", currentCount - 1, end-1);

            if (node.Children.Count() > 0)
            {
                current = node;
                goto Iterate;
            }
        }
    }
}

Ref: TreeNode.cs

Yet another tree structure: https://github.com/gt4dev/yet-another-tree-structure

Answer 8

Updated. The first version of the answer calculated the values of RemainingTime and TotalTime at the end of every iteration. Given the way the for loops are nested, it could cause long delays between updates. In order to read those values at given intervals, some changes are made.

Let's start with the Loop class. It is used to keep track of the details of every for loop, like the total amount of iterations, the current iteration and the time consumed in every iteration. To acomplish the later, two System.Diagnostic Stopwatch are used. One is kept running free, not reseted, to ease the calculation of the average time for an iteration. The other clock is reseted on every iteration to provide a value for LoopTime, used in calculations on the fly of RemainingTime and TotalTime, when accesed via the property getters. When the iteration ends, signaled by the method StopClock(), the average loop time and the related properties are updated. The values obtained here are more accurate than the ones calculated on the fly.

Its parent, LoopTimer class, is in charge of creating and storing references of Loop instances, start and stop clocks and calculate the global ETA. The method EnterLoop() is used at the beginning of the for loop. It creates a new Loop. The overload EnterLoop() with a single parameter is used in the rest of iterations to retrieve Loop instances stored in a Dictionary. The method ExitLoop(), at the end of the loop, stops the clock and updates calculations.

Functions ExitLoopRetETA() and ExitLoopRetTotalEta() are provided as replacements of ExitLoop(), to print data at the end of the loop, for testing or debugging. Method Bonus() shows how to use it. Method ShowStatus() and function GetStatus provide internal information on the Loop objects.

To show the values periodically, a Task is used, to run DoUpdate() (or DoUpdateTotal() or DoUpdateStatus())in a separate thread.

The target framework is.Net 4.0

The working classes:

using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace LoopTimer
{
  public struct TotalEta
  {
      public TimeSpan Eta;
      public TimeSpan Total;
  }

  internal class LoopTimer
  {
      // Private helper class
      private class Loop
      {
          // Declarations
          private Stopwatch _clock;
          private Stopwatch _interval_clock;

          // Constructor
          public Loop(int index, int count)
          {
              Index = index;
              Count = count;

              _clock = new Stopwatch();
              _interval_clock = new Stopwatch();
          }

          // Properties
          internal int Index { get; set; }

          internal int Count { get; private set; }

          private double _loopTimeMs;
          internal double LoopTimeMs
          {
              get
              {
                  if (_clock.IsRunning)
                  {
                      return _interval_clock.Elapsed.TotalMilliseconds;
                  }
                  else
                      return _loopTimeMs; ;
              }
          }

          private double _remainingTimeMs;
          internal double RemainingTimeMs
          {
              get
              {
                  if (_clock.IsRunning)
                      return CalculateRemainingTime();
                  else
                      return _remainingTimeMs;
              }
          }

          private double _totalTimeMs;
          internal double TotalTimeMs
          {
              get
              {
                  if (_clock.IsRunning)
                      return CalculateTotalTime();
                  else
                      return _totalTimeMs;
              }
          }

          internal TimeSpan LoopTime
          {
              get { return TimeSpan.FromMilliseconds(LoopTimeMs); }
          }

          internal TimeSpan TotalTime
          {
              get { return TimeSpan.FromMilliseconds(TotalTimeMs); }
          }

          internal TimeSpan RemainingTime
          {
              get { return TimeSpan.FromMilliseconds(RemainingTimeMs); }
          }


          // Methods

          internal void StartClock()
          {
              _clock.Start();
              _interval_clock.Start();

          }

          internal void StopClock()
          {
              _clock.Stop();
              _interval_clock.Stop();

              UpdateTimes();

              _interval_clock.Reset();

          }

          private void UpdateTimes()
          {
              //  reading clock
              double elapsed = _clock.Elapsed.TotalMilliseconds;

              // Calculating average loop time. The Stopwatch is not reseted between iterations.
              _loopTimeMs = elapsed / (Index + 1);

              // Calculating estimated remaining time =  average loop time * remaining iterations.
              _remainingTimeMs = CalculateRemainingTime();

              // Calculating estimated total time =  average loop time * iterations.
              _totalTimeMs = CalculateTotalTime();
          }

          private double CalculateRemainingTime()
          {
              // Calculating estimated remaining time =  average loop time * remaining iterations.

              double time;
              int countt = Count - Index;

              if (countt > 1)
                  time = LoopTimeMs * countt;
              else if (countt == 1)
                  time = LoopTimeMs;
              else
                  time = 0;

              return time;
          }

          private double CalculateTotalTime()
          {
              return LoopTimeMs * Count;
          }

          
      }
      // End Private helper class

      // Declarations
      private Dictionary<int, Loop> _loopDict;
      private int _loopIndex;

      // Constructor
      public LoopTimer()
      {
          _loopDict = new Dictionary<int, Loop>();
          _loopIndex = -1;
      }

      // Properties
      internal TimeSpan TotalTime
      {
          get { return TimeSpan.FromMilliseconds(TotalTimeMs); }
      }

      internal TimeSpan RemainingTime
      {
          get { return TimeSpan.FromMilliseconds(RemainingTimeMs); }
      }

      private double TotalTimeMs
      { get { return CalculateTotalTime(); } }

      private double RemainingTimeMs
      { get { return CalculateRemainingTime(); } }

      // Methods
      internal void EnterLoop(int index, int count)
      {
          Loop newLoop;

          // increase index
          _loopIndex++;

          if (!_loopDict.ContainsKey(_loopIndex))
          {
              // create new Loop
              newLoop = new Loop(index, count);
              _loopDict[_loopIndex] = newLoop;
          }
          else
          {   // retrieve Loop from Dict
              newLoop = _loopDict[_loopIndex];
          }

          newLoop.StartClock();
      }
 
      internal void EnterLoop(int index)
      {
          // increase index
          _loopIndex++;

          // retrive loop & start clock
          _loopDict[_loopIndex].Index = index;
          _loopDict[_loopIndex].StartClock();
      }

      internal void ExitLoop()
      {   // retrive loop & stop clock
          _loopDict[_loopIndex].StopClock();

          // decrease index
          _loopIndex--;
      }

      // bonus method
      internal TimeSpan ExitLoopRetETA()
      {  // retrive loop & stop clock
          _loopDict[_loopIndex].StopClock();

          // decrease index
          _loopIndex--;

          return RemainingTime;
      }

      // bonus method
      internal TotalEta ExitLoopRetTotalEta()
      {
          TotalEta retval;

          retval.Eta = ExitLoopRetETA();
          retval.Total = TotalTime;

          return retval;
      }

      // debug method
      internal void ShowStatus()
      {
          Console.WriteLine("Status:");
          Console.WriteLine(" RemainingTime:");
          for (int i = 0; i < _loopDict.Count; i++)
          {
              TimeSpan time = _loopDict[i].RemainingTime;
              Console.WriteLine(string.Format(" Loop: {0} Value: {1}", i, time.ToString()));
          }
          Console.WriteLine();
      }

      // debug method
      internal TotalEta[] GetStatus()
      {
          TotalEta[] retArr = new TotalEta[_loopDict.Count];
          TotalEta retval;

          for (int i = 0; i < _loopDict.Count; i++)
          {
              retval = new TotalEta();

              retval.Eta = _loopDict[i].RemainingTime;
              retval.Total = _loopDict[i].TotalTime;

              retArr[i] = retval;
          }
          return retArr;
      }

      private double CalculateRemainingTime()
      {
          double max, time;
          max = 0;

          // Remaining Time, the greater of all
          for (int i = 0; i < _loopDict.Count; i++)
          {
              time = _loopDict[i].RemainingTimeMs;
              if (time > max)
                  max = time;
          }

          return max;
      }

      // Total Time, bonus
      private double CalculateTotalTime()
      {
          double max, time;
          max = 0;

          // Total Time, the greater of all  
          for (int i = 0; i < _loopDict.Count; i++)
          {
              time = _loopDict[i].TotalTimeMs;
              if (time > max)
                  max = time;
          }

          return max;
      }
  }
}

The sample program:

using System;
using System.Threading;
using System.Threading.Tasks;


namespace LoopTimer
{
  class Solution
  {
      static CancellationTokenSource ts;

      static void Main(string[] args)
      {
          Console.Clear();

          LoopTimer lm = new LoopTimer();

          var random = new Random();

          // For easy change test parameters
          int minRndCount = 1;
          int maxRndCount = 10;
          int minRndSleep = 100;
          int maxRndSleep = 1000;

          // A task to update console, with cancellation token
          ts = new CancellationTokenSource();
          Task updater = new Task(() => DoUpdate(lm), ts.Token);
          // Uncomment to show estimated total time.
          //Task updater = new Task(() => DoUpdateTotal(lm), ts.Token);
          // Uncomment to show estimated total time and internal values of every loop.
          //Task updater = new Task(() => DoUpdateStatus(lm), ts.Token);

          // Simulate initiation delay
          Thread.Sleep(random.Next(minRndSleep, maxRndSleep));
          // Console.WriteLine("initiate");

          updater.Start();

          int intCountL1 = random.Next(minRndCount, maxRndCount);
          for (int loop1 = 0; loop1 <= intCountL1; loop1++)
          {
              // Entering loop1
              if (loop1 == 0)
                  lm.EnterLoop(loop1, intCountL1);
              else
                  lm.EnterLoop(loop1);

              // Simulate loop1 delay
              //Console.WriteLine("\tloop1");
              Thread.Sleep(random.Next(minRndSleep, maxRndSleep));

              int intCountL2 = random.Next(minRndCount, maxRndCount);
              for (int loop2 = 0; loop2 <= intCountL2; loop2++)
              {
                  // Entering loop2
                  if (loop2 == 0)
                      lm.EnterLoop(loop2, intCountL2);
                  else
                      lm.EnterLoop(loop2);

                  // Simulate loop2 delay
                  //Console.WriteLine("\t\tloop2");
                  Thread.Sleep(random.Next(minRndSleep, maxRndSleep));

                  int intCountL3 = random.Next(minRndCount, maxRndCount);
                  for (int loop3 = 0; loop3 <= intCountL3; loop3++)
                  {
                      // Entering loop3
                      if (loop3 == 0)
                          lm.EnterLoop(loop3, intCountL3);
                      else
                          lm.EnterLoop(loop3);

                      // Simulate loop3 delay
                      //Console.WriteLine("\t\t\tloop3");
                      Thread.Sleep(random.Next(minRndSleep, maxRndSleep));

                      int intCountL4 = random.Next(minRndCount, maxRndCount);
                      for (int loop4 = 0; loop4 <= intCountL4; loop4++)
                      {
                          // Entering loop4
                          if (loop4 == 0)
                              lm.EnterLoop(loop4, intCountL4);
                          else
                              lm.EnterLoop(loop4);

                          // Simulate loop4 delay
                          //Console.WriteLine("\t\t\t\tloop4");
                          Thread.Sleep(random.Next(minRndSleep, maxRndSleep));

                          // Exiting loop4
                          lm.ExitLoop();
                      }
                      // Exiting loop3
                      lm.ExitLoop();
                  }
                  // Exiting loop2
                  lm.ExitLoop();
              }
              // Exiting loop1
              lm.ExitLoop();
          }
          ts.Cancel();
      }

      static private void DoUpdate(LoopTimer lm)
      {
          char[] animchar = { '|', '/', '-', '\\' };
          int index = 0;

          Thread.Sleep(100);

          while (true)
          {
              TimeSpan eta = lm.RemainingTime;

              Console.SetCursorPosition(0, 0);
              Console.Write(string.Format(" {4} ETA: {0} Days, {1} Hours, {2} Minutes, {3} Seconds", eta.Days.ToString().PadLeft(3, '0'), eta.Hours.ToString().PadLeft(2, '0'), eta.Minutes.ToString().PadLeft(2, '0'), eta.Seconds.ToString().PadLeft(2, '0'), animchar[index].ToString()));

              if (++index > 3)
                  index = 0;
              Thread.Sleep(1000);

              ts.Token.ThrowIfCancellationRequested();
          }
      }

      /*
        This method is provided as a sample on displaying the estimated total time.
       */
      static private void DoUpdateTotal(LoopTimer lm)
      {
          char[] animchar = { '|', '/', '-', '\\' };
          int index = 0;

          Thread.Sleep(100);

          while (true)
          {
              TimeSpan eta = lm.RemainingTime;
              TimeSpan total = lm.TotalTime;

              Console.SetCursorPosition(0, 0);
              Console.Write(string.Format(" {4} ETA: {0} Days, {1} Hours, {2} Minutes, {3} Seconds", eta.Days.ToString().PadLeft(3, '0'), eta.Hours.ToString().PadLeft(2, '0'), eta.Minutes.ToString().PadLeft(2, '0'), eta.Seconds.ToString().PadLeft(2, '0'), animchar[index].ToString()));
              Console.Write(string.Format("\n Total: {0} Days, {1} Hours, {2} Minutes, {3} Seconds", total.Days.ToString().PadLeft(3, '0'), total.Hours.ToString().PadLeft(2, '0'), total.Minutes.ToString().PadLeft(2, '0'), total.Seconds.ToString().PadLeft(2, '0')));

              if (++index > 3)
                  index = 0;
              Thread.Sleep(1000);

              ts.Token.ThrowIfCancellationRequested();
          }
      }

      /*
       This method is provided as a sample on displaying the estimated total time, and
       the internal values of every loop.
      */
      static private void DoUpdateStatus(LoopTimer lm)
      {
          char[] animchar = { '|', '/', '-', '\\' };
          int index = 0;

          Thread.Sleep(100);

          while (true)
          {
              TimeSpan eta = lm.RemainingTime;
              TimeSpan total = lm.TotalTime;
              TotalEta[] status = lm.GetStatus();

              Console.SetCursorPosition(0, 0);
              Console.Write(string.Format(" {4} ETA: {0} Days, {1} Hours, {2} Minutes, {3} Seconds", eta.Days.ToString().PadLeft(3, '0'), eta.Hours.ToString().PadLeft(2, '0'), eta.Minutes.ToString().PadLeft(2, '0'), eta.Seconds.ToString().PadLeft(2, '0'), animchar[index].ToString()));
              Console.Write(string.Format("\n Total: {0} Days, {1} Hours, {2} Minutes, {3} Seconds", total.Days.ToString().PadLeft(3, '0'), total.Hours.ToString().PadLeft(2, '0'), total.Minutes.ToString().PadLeft(2, '0'), total.Seconds.ToString().PadLeft(2, '0')));
              Console.WriteLine();

              int loop = 0;

              foreach (var item in status)
              {
                  Console.Write(string.Format("\n Loop: {0} ETA: {1}    \tTotal: {2}", loop, item.Eta.ToString(@"hh\:mm\:ss\.FFFF"), item.Total.ToString(@"hh\:mm\:ss\.FFFF")));
                  loop++;
              }

              if (++index > 3)
                  index = 0;

              Thread.Sleep(1000);

              ts.Token.ThrowIfCancellationRequested();
          }
      }

      /*
        This method is provided as a sample for variations on 
        the ExitLoopRet method. Uses in-place calls.
      */
      static internal void Bonus()
      {
          TotalEta remVal;
          TimeSpan remTime;

          LoopTimer lm = new LoopTimer();

          Console.Clear();

          // easy change test parameters
          var random = new Random();
          int minRndCount = 1;
          int maxRndCount = 5;

          int maxRndSleep = 1000;

         
          // First, outer loop
          int intCountL1 = random.Next(minRndCount, maxRndCount);

          for (int i = 0; i < intCountL1; i++)
          {
              if (i == 0)
                  lm.EnterLoop(i, intCountL1);
              else
                  lm.EnterLoop(i);

              Console.WriteLine(string.Format("\nLoop1 begin iteration: {0} of {1}. Will work(sleep) for {2} ms.", i, intCountL1 - 1, maxRndSleep));
              Thread.Sleep(maxRndSleep);

              // Second, middle loop
              int intCountL2 = random.Next(minRndCount, maxRndCount);

              for (int j = 0; j < intCountL2; j++)
              {
                  if (j == 0)
                      lm.EnterLoop(j, intCountL2);
                  else
                      lm.EnterLoop(j);

                  Console.WriteLine(string.Format("\n\tLoop2 begin iteration: {0} of {1}. Will work(sleep) for {2} ms.", j, intCountL2 - 1, maxRndSleep));
                  Thread.Sleep(maxRndSleep);

                  // Third, inner loop
                  int intCountL3 = random.Next(minRndCount, maxRndCount);
                  for (int k = 0; k < intCountL3; k++)
                  {
                      if (k == 0)
                          lm.EnterLoop(k, intCountL3);
                      else
                          lm.EnterLoop(k);

                      Console.WriteLine(string.Format("\n\t\tLoop3 begin iteration: {0} of {1}. Will work(sleep) for {2} ms.", k, intCountL3 - 1, maxRndSleep));
                      Thread.Sleep(maxRndSleep);

                      lm.ExitLoop();
                   
                      Console.WriteLine(string.Format("\n\t\tLoop3 end iteration: {0} of {1}", k, intCountL3 - 1));
                      lm.ShowStatus();
                  }

                  remTime = lm.ExitLoopRetETA();
                
                  Console.WriteLine(string.Format("\n\tLoop2 end iteration: {0} of {1}", j, intCountL2 - 1));
                  Console.WriteLine("\t\tRem: " + remTime.ToString());
              }

              remVal = lm.ExitLoopRetTotalEta();
              
              Console.WriteLine(string.Format("\nLoop1 end iteration: {0} of {1}", i, intCountL1 - 1));
              Console.WriteLine("\t\tTot: " + remVal.Total.ToString());
              Console.WriteLine("\t\tRem: " + remVal.Eta.ToString());
          }
      }

  }
}