We Keep Coding

Is it possible to clear objects with the get property after calling the class?

this below to sample code;
private ExampleStatus _status;
public ExampleStatus status
{
get
{
if (_status == null) _status = new ExampleStatus();
//if (_status.receivedData) _status.receivedData = false; //this line is incorrect !
return _status;
}
}
public class ExampleStatus
{
public int Id { get; set; }
public string Name { get; set; }
public bool receivedData { get; set; }
//I don't want to use this method
public void Clear()
{
Id = 0;
Name = string.Empty;
receivedData = false;
}
}
int stateType = 0;
void ContinuousLoop(ExampleStatus statusObj)
{
while (true)
{
//I don't want to use the options below
//statusObj.Clear();
//or
//statusObj = new ExampleStatus();
if (stateType == 0)
{
statusObj.Id = 0;
statusObj.Name = "Firs Status";
}
else if (stateType == 1)
{
statusObj.Id = 1;
statusObj.Name = "Second Status";
statusObj.receivedData = true;
}
else if (stateType == 2)
{
statusObj.Id = 2;
statusObj.Name = "Third Status";
}
}
}
void RunThread()
{
var t1 = new Thread(() =>
{
ContinuousLoop(status);
});
t1.Start();
}
Is it possible to set default values ​​without a method or new instance, as shown in the example?
Actually that's why I'm asking this question:
I will use the class I have defined in many places. I will need to add a block of code, such as the Clear method, to every place I use it.
I'm also curious about one more thing. If I assign a new instance every time to reset my objects, does this cause problems in memory?
I know more or less how garbage collections work. However, they say that in practice it does not work as said in theory.
So if I add "IDisposable" to my Class, it would tell the garbage collector: Welcome, I'm a litter. Will you take me too?

Property seems to be changing between method calls, but no code is supposed to be changing it

I have an Octet class that is suppose to "package" eight samples and then send them forward. It has methods to add a new sample, check if it is already full, and to extract a Frame datastructure built from the eight values from the Octet.
The Octet class throws two kinds of exceptions: "cannot extract because not yet full" and "cannot add sample because already full". For that, the client code should check if full before calling Add, and extract as soon as is full, as well as to reset it (quite a lame class contract, to be honest).
The problem is: I am getting the two kinds of errors, even though the client class - the only one using Octet - seems to be performing the checks correctly before the operations that throw, but even though the error conditions are being hit. To make matters worse, when I check the values when debugger breaks, they are correct, that is, the exceptions should not be throwing!
public class Client
{
private Octet _octet = new Octet();
void ProcessNewSamples(IEnumerable<int> newSamples)
{
foreach (int sample in newSamples)
{
if (!_octet.IsFull)
{
_octet.Add(sample);
}
if (_octet.IsFull)
{
var frame = _octet.ExtractFrame();
this.SendElsewhere(frame);
_octet.Reset();
}
}
}
}
public class Octet
{
const int ARRAY_SIZE = 8;
int[] _samples = new int[ARRAY_SIZE];
int _index = 0;
public bool IsFull { get { return _index >= 8; } }
public void Add(int sample)
{
if (IsFull)
{
throw new InvalidOperationException();
}
else
_samples[_index++] = sample;
}
public Frame<int> ExtractFrame()
{
if (!IsFull)
throw new InvalidOperationException();
else
return new Frame<int>(_samples);
}
public void Reset()
{
_samples = new int[ARRAY_SIZE];
_index = 0;
}
}

As mentioned in the comment, you should place a lock if your function is accessed in parallel.
If SendElsewhere is fast, I simply would place the lock around the function:
void ProcessNewSamples(IEnumerable<int> newSamples)
{
lock (this)
{
foreach (int sample in newSamples)
{
if (!_octet.IsFull)
{
_octet.Add(sample);
}
if (_octet.IsFull)
{
var frame = _octet.ExtractFrame();
this.SendElsewhere(frame);
_octet.Reset();
}
}
}
}
Otherwise I would collect all frames and send them afterwards:
void ProcessNewSamples(IEnumerable<int> newSamples)
{
var frames = new List<Frame>();
lock (this)
{
foreach (int sample in newSamples)
{
if (!_octet.IsFull)
{
_octet.Add(sample);
}
if (_octet.IsFull)
{
var frame = _octet.ExtractFrame();
frames.Add(frame);
_octet.Reset();
}
}
}
foreach (var frame in frames)
{
this.SendElsewhere(frame)
}
}

Creating list/array of class instances?

I'm fairly new to C# and I have just learned about creating custom classes. The problem is, I can't figure out how to take the 40~65 instances of this class and put them in a list/array (whichever one I need) where I can locate and choose one based on an attribute defined in it.
Here's the class I have created right now:
public class Team
{
protected int teamNum;
protected double averageMatchPoints;
protected string location;
protected int matchesPlayed;
protected int matchesPending;
protected int blowouts;
//Team Number
public void SetNumber(int num)
{
teamNum = num;
}
public int GetNumber()
{
return teamNum;
}
//Average Points per match
public void AverageMatchPoints(double p)
{
averageMatchPoints = p;
}
public double GetAverageMatchPoints()
{
return averageMatchPoints;
}
//location information
public void SetLocation(string l)
{
location = l;
}
public string GetLocation()
{
return location;
}
//Number of Played Matches
public void PlayedMatches(int mat)
{
matchesPlayed = mat;
}
public int GetPlayedMatches()
{
return matchesPlayed;
}
//Number of matches pending (not played)
public void PendingMatches(int pen)
{
matchesPending = pen;
}
public int GetPendingMatches()
{
return matchesPending;
}
//Number of Blowouts (matches where the robot was disbaled for any number of reasons)
public void SetBlowouts(int b)
{
blowouts = b;
}
public int GetBlowouts()
{
return blowouts;
}
}
Now, if I had 40~65 of these teams competing at an event and I made an instance of this class for each one, how would I populate a combobox with each team number (teamNum) and then locate one specific team out of all the instances in the program by their team numbers?

I recommend a dictionary!
// Declared somewhere
private Dictionary<int, Team> _teamDictionary = new Dictionary<int, Team>();
.
.
.
//Initialization code - I assume you have gotten your teams from a database or somewhere?
foreach (var team in myTeamsList)
{
_teamDictionary.Add(team.teamNum, team);
}
.
.
.
// Later when you want to locate a team:
var team = _teamDictionary[selectedTeamNum];

Have you tried creating a List yet?
List<Team> Teams { get; set; }
You can then bind your combobox to the list/collection/IEnumerable of all the teams that you have. To initialize the teams up to 40/60 do the following?
for(int i = 0; i < 60; i++)
{
Team t = new Team();
t.Name = "Team 1";
t.TeamNumber = i + 1;
Teams.Add(t);
}

List<Team> allTheTeams = new List<Team>();
for(var i = 0; i < 65; i++){
allTheTeams.Add(new Team { teamNum = i });
}
And to get the team with number 34:
allTheTeams.FirstOrDefault(x => x.teamNum == 34);

Like this:
Add a constructor to your class that takes the teamnumber:
(this is the best solution if every team needs to have a number. So you can not forget to set the team number as you can not create an object of type team without setting the number in the constructor)
public class Team
{
protected int _teamNum;
public Team(int teamNum)
{
_teamNum = teamNum;
}
public int getTeamNum()
{
return _teamNum;
}
//more logic
}
Populate a dictionary, the comboBox and get a team for its number:
Dictionary<int, Team> dictionary = new Dictionary<int, Team>();
int teamNum = 1;
// Add your Teams to a dictionary (example)
dictionary.Add(teamNum ,new Team(teamNum++));
dictionary.Add(teamNum, new Team(teamNum++));
dictionary.Add(teamNum, new Team(teamNum++));
// Populate a comboBox
foreach(KeyValuePair<int,Team> kvp in dictionary)
{
comboBox1.Items.Add(kvp.Value.getTeamNum().ToString());
}
// get a team for a given teamNumer
int targetTeamNumber = 2;
if (dictionary.ContainsKey(targetTeamNumber))
{
Team team = dictionary[targetTeamNumber];
// do something with the team
}

Trying to make it so when i click on my windows forms button, the next 3 numbers from my textfile are shown

Here is the code below.
I am trying to make it so that when I click on the nextButton button it cycles to the next 3 numbers in my textfile. I cant figure out ow, what i have here should work :[
namespace GPSProject
{
class dataPoints
{
public int Count { get { return Points.Count; } }
List<dataPoint> Points;
//string p;
public dataPoints(/*string path*/)
{
Points = new List<dataPoint>();
// p = path;
TextReader tr = new StreamReader(/*p*/"C:/Test.txt");
string input;
while ((input = tr.ReadLine()) != null)
{
string[] bits = input.Split(',');
dataPoint a = new dataPoint(bits[0], bits[1], bits[2]);
Points.Add(a);
}
tr.Close();
}
internal dataPoint getItem(int p)
{
if (p < Points.Count)
{
return Points[p];
}
else
return null;
}
}
}
Above is the class that breaks down the textfile into inidividual numbers.
namespace GPSProject
{
public partial class Form1 : Form
{
private int count;
internal dataPoints myDataPoints;
public Form1()
{
myDataPoints = new dataPoints();
InitializeComponent();
}
private void buttonNext_Click(object sender, EventArgs e)
{
{
count++;
if (count == (myDataPoints.Count))
{
count = 0;
}
dataPoint a = myDataPoints.getItem(count);
textBoxLatitude.Text = a.CurLatitude;
textBoxLongtitude.Text = a.CurLongtitude;
textBoxElevation.Text = a.CurElevation;
}
}
}
}
Above is the Windows form
namespace GPSProject
{
class dataPoint
{
private string latitude;
private string longtitude;
private string elevation;
public dataPoint() //Overloaded incase no value available
{
latitude = "No Latitude Specified";
longtitude = "No Longtitude Specified";
elevation = "No Elevation Specified";
}
public dataPoint(string Latitude, string Longtitude, string Elevation)
{
// TODO: Complete member initialization
this.latitude = Latitude;
this.longtitude = Longtitude;
this.elevation = Elevation;
}
public string CurLongtitude { get { return this.longtitude; } }
public string CurLatitude { get { return this.latitude; } }
public string CurElevation { get { return this.elevation; } }
}
}
And finally this is the class the holds the numbers. The numbers i am trying to get the textboxes to show are cycles of CurLongtitude/Latitue/Elevation

First thing to do would be to create a proper vessle for your data: the DataPoint Entity:
class DataPoint
{
// Option 1: Field + read only property
private string _latitude;
public string Latitude { get { return _latitude; } }
// Option 2: Property + compiler generated field
public string Longitude { get; private set; }
public string Elevation { get; private set; }
// Constructor
public DataPoint(string latitude, string longtitude, string elevation)
{
// Internally in this class we use fields
_latitude = latitude;
// Unless we use property option 2
this.Longitude = longitude;
this.Elevation = elevation;
}
}
Next we could add a static method to the DataPoint class to load the data points from disk:
public static List<DataPoint> LoadFromFile (string filename)
{
// The .NET framework has a lot of helper methods
// be sure to check them out at MSDN
// Read the contents of the file into a string array
string[] lines = File.ReadAllLines(filename);
// Create the result List
List<DataPoint> result = new List<DataPoint>();
// Parse the lines
for (string line in lines)
{
string[] bits = line.Split(',');
// We're using our own constructor here
// Do watch out for invalid files, resulting in out-of-index Exceptions
DataPoint dataPoint = new DataPoint(bits[0], bits[1], bits[2]);
result.Add(dataPoint);
}
return result;
}
Now that we have all the building blocks. Let's make the application:
public partial class Form1 : Form
{
private int _index;
private List<DataPoint> _dataPoints;
public Form1()
{
// Since this is a simple test application we'll do the call here
_dataPoints = DataPoint.LoadFromFile(#"C:\Test.txt");
InitializeComponent();
}
private void buttonNext_Click(object sender, EventArgs e)
{
// Cycle the data points
_index++;
if (_index == _dataPoints.Count)
{
_index = 0;
}
// Get the specific data point
DataPoint dataPoint = _dataPoints[_index];
// The empty texts are UI only, so we could check them here
if (dataPoint.Latitude == null || dataPoint.Latitude == "")
{
textBoxLatitude.Text = "No Latitude Specified";
}
else
{
textBoxLatitude.Text = dataPoint.Latitude;
}
// A shorter, inline version
textBoxLongtitude.Text = String.IsNullOrEmpty(dataPoint.Longitude) ? "No Longitude Specified" : dataPoint.Longitude;
// Or if we don't care about empty texts
textBoxElevation.Text = dataPoint.Elevation;
}
}
Of course there are lots of ways to make the code even shorter, or to use modern techniques like LINQ, but I've tried not to go too far from your existing code. I haven't tried the code, I typed it here on SO :)
Also please be careful in how you format your code. Proper casing and following standards makes your code a lot easier to read by others.
MSDN has a lot of good examples and extensive documentation on the .NET Framework classes.

traveling salesman problem, 2-opt algorithm c# implementation

Can someone give me a code sample of 2-opt algorithm for traveling salesman problem. For now im using nearest neighbour to find the path but this method is far from perfect, and after some research i found 2-opt algorithm that would correct that path to the acceptable level. I found some sample apps but without source code.

So I got bored and wrote it. It looks like it works, but I haven't tested it very thoroughly. It assumes triangle inequality, all edges exist, that sort of thing. It works largely like the answer I outlined. It prints each iteration; the last one is the 2-optimized one.
I'm sure it can be improved in a zillion ways.
using System;
using System.Collections.Generic;
using System.Linq;
namespace TSP
{
internal static class Program
{
private static void Main(string[] args)
{
//create an initial tour out of nearest neighbors
var stops = Enumerable.Range(1, 10)
.Select(i => new Stop(new City(i)))
.NearestNeighbors()
.ToList();
//create next pointers between them
stops.Connect(true);
//wrap in a tour object
Tour startingTour = new Tour(stops);
//the actual algorithm
while (true)
{
Console.WriteLine(startingTour);
var newTour = startingTour.GenerateMutations()
.MinBy(tour => tour.Cost());
if (newTour.Cost() < startingTour.Cost()) startingTour = newTour;
else break;
}
Console.ReadLine();
}
private class City
{
private static Random rand = new Random();
public City(int cityName)
{
X = rand.NextDouble() * 100;
Y = rand.NextDouble() * 100;
CityName = cityName;
}
public double X { get; private set; }
public double Y { get; private set; }
public int CityName { get; private set; }
}
private class Stop
{
public Stop(City city)
{
City = city;
}
public Stop Next { get; set; }
public City City { get; set; }
public Stop Clone()
{
return new Stop(City);
}
public static double Distance(Stop first, Stop other)
{
return Math.Sqrt(
Math.Pow(first.City.X - other.City.X, 2) +
Math.Pow(first.City.Y - other.City.Y, 2));
}
//list of nodes, including this one, that we can get to
public IEnumerable<Stop> CanGetTo()
{
var current = this;
while (true)
{
yield return current;
current = current.Next;
if (current == this) break;
}
}
public override bool Equals(object obj)
{
return City == ((Stop)obj).City;
}
public override int GetHashCode()
{
return City.GetHashCode();
}
public override string ToString()
{
return City.CityName.ToString();
}
}
private class Tour
{
public Tour(IEnumerable<Stop> stops)
{
Anchor = stops.First();
}
//the set of tours we can make with 2-opt out of this one
public IEnumerable<Tour> GenerateMutations()
{
for (Stop stop = Anchor; stop.Next != Anchor; stop = stop.Next)
{
//skip the next one, since you can't swap with that
Stop current = stop.Next.Next;
while (current != Anchor)
{
yield return CloneWithSwap(stop.City, current.City);
current = current.Next;
}
}
}
public Stop Anchor { get; set; }
public Tour CloneWithSwap(City firstCity, City secondCity)
{
Stop firstFrom = null, secondFrom = null;
var stops = UnconnectedClones();
stops.Connect(true);
foreach (Stop stop in stops)
{
if (stop.City == firstCity) firstFrom = stop;
if (stop.City == secondCity) secondFrom = stop;
}
//the swap part
var firstTo = firstFrom.Next;
var secondTo = secondFrom.Next;
//reverse all of the links between the swaps
firstTo.CanGetTo()
.TakeWhile(stop => stop != secondTo)
.Reverse()
.Connect(false);
firstTo.Next = secondTo;
firstFrom.Next = secondFrom;
var tour = new Tour(stops);
return tour;
}
public IList<Stop> UnconnectedClones()
{
return Cycle().Select(stop => stop.Clone()).ToList();
}
public double Cost()
{
return Cycle().Aggregate(
0.0,
(sum, stop) =>
sum + Stop.Distance(stop, stop.Next));
}
private IEnumerable<Stop> Cycle()
{
return Anchor.CanGetTo();
}
public override string ToString()
{
string path = String.Join(
"->",
Cycle().Select(stop => stop.ToString()).ToArray());
return String.Format("Cost: {0}, Path:{1}", Cost(), path);
}
}
//take an ordered list of nodes and set their next properties
private static void Connect(this IEnumerable<Stop> stops, bool loop)
{
Stop prev = null, first = null;
foreach (var stop in stops)
{
if (first == null) first = stop;
if (prev != null) prev.Next = stop;
prev = stop;
}
if (loop)
{
prev.Next = first;
}
}
//T with the smallest func(T)
private static T MinBy<T, TComparable>(
this IEnumerable<T> xs,
Func<T, TComparable> func)
where TComparable : IComparable<TComparable>
{
return xs.DefaultIfEmpty().Aggregate(
(maxSoFar, elem) =>
func(elem).CompareTo(func(maxSoFar)) > 0 ? maxSoFar : elem);
}
//return an ordered nearest neighbor set
private static IEnumerable<Stop> NearestNeighbors(this IEnumerable<Stop> stops)
{
var stopsLeft = stops.ToList();
for (var stop = stopsLeft.First();
stop != null;
stop = stopsLeft.MinBy(s => Stop.Distance(stop, s)))
{
stopsLeft.Remove(stop);
yield return stop;
}
}
}
}

Well, your solution to TSP is always going to be far from perfect. No code, but here's how to go about 2-Opt. It's not too bad:
You need a class called Stop that has a Next, Prev, and City property, and probably a Stops property that just returns the array containing Next and Prev.
When you link them together, we'll call that a Tour. Tour has a Stop property (any of the stops will do), and an AllStops property, whose getter just walks the stops and returns them
You need a method that takes a tour and returns its cost. Let's call that Tour.Cost().
You need Tour.Clone(), which just walks the stops and clones them individually
You need a method that generates the set of tours with two edges switched. Call this Tour.PossibleMutations()
Start with your NN solution
Call PossibleMutations() on it
Call Cost() on all of them and take the one with the lowest result
Repeat until the cost doesn't go down

If the problem is euclidian distance and you want the cost of the solution produced by the algorithm is within 3/2 of the optimum then you want the Christofides algorithm. ACO and GA don't have a guaranteed cost.