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C# exclude numbers from a list in random generation

I am making a tic tac toe game and I am making it to be unbeatable
but first I have to let the computer know the rules.
I'm stuck in a step that is => when it's the computer's turn and we have just started the game so no win case so it's up to the computer to generate a random number that will be the computer's choice ( the block where he mark X or O )
so I need it to generate a number from 1 to 9 but by excluding the already used blocks ( numbers ).
I tried doing that by making a list and adding a number every time the human player used a block but I can't find a way to use those numbers from the list as exclusion for the random choice of the computer.
Here is what I tried and thnx in advance:
//random
List<int> cas = new List<int>();
if (c1 == true)
{
cas.Add(1);
}
if (c2 == true)
{
cas.Add(2);
}
if (c3 == true)
{
cas.Add(3);
}
if (c4 == true)
{
cas.Add(4);
}
if (c5 == true)
{
cas.Add(5);
}
if (c6 == true)
{
cas.Add(6);
}
if (c7 == true)
{
cas.Add(7);
}
if (c8 == true)
{
cas.Add(8);
}
if (c9 == true)
{
cas.Add(9);
}
for (int i = 0; i < cas.Count; i++)
{
random_except_list(cas[]);
}
public static int random_except_list(int[] x)
{
Random r = new Random();
int result = r.Next(1, 9 - );
for (int i = 0; i < x.Length; i++)
{
if (result < x[i])
return result;
result++;
}
return result;
}

Lets have possible places to use:
List<int> possible = Enumerable.Range(1,9).ToList(); // create a list and add 1-9
and used places:
List<int> used = new List<int>();
Random rnd = new Random();
Now everytime we generate a random number in the range of possible list count as index and remove it from there and move it to used:
int index = rnd.Next(0, possible.Count);
used.Add(possible[index]);
possible.RemoveAt(index);
for user its just enough to check if it exists in the used so the acceptable number should be:
!used.Any(x=> x== NumberUserHaveChosen)
So the first time the random number can be 0-8 (as possible.Count==9) and take from it at random index.
the second time the random number can be 0-7 (as possible.Count==8) and take from it at random index.
and so on... while the possible.Count != 0
in this case there is no need to generate random numbers several times that finally it won't exist in our used List.
Several years ago I was working on a Sudoku algorithm, and what I was trying to achieve was to generate a valid solved sudoku table in minimum time possible, i get to the conclusion that I should replace the algorithm that each time I generate a number I have to check some lists to make sure the number was not generated before, as count of numbers were increasing these comparisons would become more and more. for example when only the number 4 is remaining, I should generate random numbers till I get 4. so I used this approach and the result was amazing.

I think you should do something like this:
public static int random_except_list(List<int> x)
{
Random r = new Random();
int result = 0;
while (true)
{
result = r.Next(1, 10);
if (!x.Contains(result))
return result;
}
}

Just trying to use what you have written (more or less), but changing the method to take a List<int> which is what you are building, I would write the method using LINQ like this (except I would create a static Random variable and keep it between calls):
public static int random_except_list(List<int> x) => Enumerable.Range(1, 9).Where(n => !x.Contains(n)).ToList()[new Random().Next(0, 9 - x.Count)];
However, you can implement the same idea in a more explicit way using procedural code:
public static int random_except_list_explicit(List<int> x) {
// First, generate a list of possible answers by skipping the except positions in x
var possibles = new List<int>();
for (int i = 1; i <= 9; i++)
if (!x.Contains(i))
possibles.Add(i);
// now pick a random member of the possible answers and return it
return possibles[new Random().Next(0, possibles.Count)];
}

I believe it is better to work with positions left. So user or computer select from all open positions:
using System;
using System.Collections.Generic;
class app
{
public static int random_except_list(List<int> openPositions)
{
Random r = new Random();
int index = r.Next(openPositions.Count - 1);
int result = openPositions[index];
openPositions.RemoveAt(index);
return result;
}
static void Main()
{
List<int> openPositions = new List<int>();
for (int i = 1; i < 10; i++)
{
openPositions.Add(i);
}
bool turn = false;
while (openPositions.Count > 0)
{
foreach (int value in openPositions)
{
Console.Write(value + " ");
}
Console.WriteLine();
if (!turn)
{
while (true)
{
Console.WriteLine("Choose your Position");
ConsoleKeyInfo key = Console.ReadKey();
int num = (int)key.KeyChar - 48;
if (openPositions.Contains(num))
{
openPositions.Remove(num);
Console.WriteLine();
break;
}
else Console.Write(" is not Valid: ");
}
}
else
{
int compPos = random_except_list(openPositions);
Console.WriteLine("Computer choose: " + compPos);
}
turn = !turn;
}
Console.WriteLine("No positions left");
Console.ReadKey();
}
}

Prevent System.StackOverflowException when recursively calling a method

I am new to c# (or coding in general) and I guess this question is really stupid and confusing (I know I'm doing it a hard way) but please help me.
I'm trying to make a minesweeper with form app. I made a 10 x 10 of buttons and if you click it, number of mines around it will be revealed. If a mine is there "F" (the first letter of "False") will appear.
There's a constructor that contains the button, x and y position, list of surrounding blocks, number of mines around it, and a boolean that indicates if there's a mine or not.
What I tried to do was to make the 8 surrounding blocks (from the list) cleared when the player clicked a block with no mine around it and if the block surrounding that block also doesn't have any mine around it, these blocks that surrounding that block will also be cleared. The method uses foreach to reveal and check the number of mines around that block. If there's no mines, same method will be applied to that block (calling the method recursively). The problem is that I keep getting System.StackOverflowException.
I somehow understand why it's happening but I just can't come up with the other way.
//scroll to the bottom for the method with the problem
private void Form1_Load(object sender, EventArgs e)
{
Random random = new Random();
Button[,] buttons = new Button[10, 10]
{
{ r0c0, r0c1, r0c2, r0c3, r0c4, r0c5, r0c6, r0c7, r0c8, r0c9 },
{ r1c0, r1c1, r1c2, r1c3, r1c4, r1c5, r1c6, r1c7, r1c8, r1c9 },
{ r2c0, r2c1, r2c2, r2c3, r2c4, r2c5, r2c6, r2c7, r2c8, r2c9 },
{ r3c0, r3c1, r3c2, r3c3, r3c4, r3c5, r3c6, r3c7, r3c8, r3c9 },
{ r4c0, r4c1, r4c2, r4c3, r4c4, r4c5, r4c6, r4c7, r4c8, r4c9 },
{ r5c0, r5c1, r5c2, r5c3, r5c4, r5c5, r5c6, r5c7, r5c8, r5c9 },
{ r6c0, r6c1, r6c2, r6c3, r6c4, r6c5, r6c6, r6c7, r6c8, r6c9 },
{ r7c0, r7c1, r7c2, r7c3, r7c4, r7c5, r7c6, r7c7, r7c8, r7c9 },
{ r8c0, r8c1, r8c2, r8c3, r8c4, r8c5, r8c6, r8c7, r8c8, r8c9 },
{ r9c0, r9c1, r9c2, r9c3, r9c4, r9c5, r9c6, r9c7, r9c8, r9c9 }
};
Square[,] squares = new Square[10, 10];
for (int i = 0, ii = 0, iii = 0; i < 100; i++, ii++)
{
if (ii == 10)
{
ii = 0;
iii++;
}
squares[ii, iii] = new Square(i, buttons[ii, iii], ii, iii, 0, true);
}
List<int> randoms = new List<int>();
for (int i = 0; i < 10; i++)
{
int ii = random.Next(100);
if (!randoms.Contains(ii))
{
squares[ii % 10, ii / 10].setSafe(false);
}
else
{
i--;
}
randoms.Add(ii);
}
for (int i = 0; i < 10; i++)
{
for (int ii = 0; ii < 10; ii++)
{
for (int iii = -1; iii < 2; iii++)
{
for (int iiii = -1; iiii < 2; iiii++)
{
try
{
if (squares[i + iii, ii + iiii].getSafe() == false)
squares[i, ii].addNumber();
}
catch (System.IndexOutOfRangeException)
{
}
}
//if (squares[i, ii].getSafe() == false) squares[i, ii].getButton().Text = squares[i, ii].getSafe().ToString();
//else squares[i, ii].getButton().Text = squares[i, ii].getNumber().ToString();
}
}
}
for (int i = 0; i < 10; i++)
{
for (int ii = 0; ii < 10; ii++)
{
for (int iii = -1; iii < 2; iii++)
{
for (int iiii = -1; iiii < 2; iiii++)
{
try
{
squares[i, ii].addList(squares[i + iii, ii + iiii]);
}
catch (System.IndexOutOfRangeException)
{
}
}
}
}
}
}
Here's the Square class:
public class Square
{
int id;
Button button;
int x;
int y;
int number;
bool safe;
List<Square> list = new List<Square>();
public Square(int id, Button button, int x, int y, int number, bool safe)
{
this.id = id;
this.button = button;
this.x = x;
this.y = y;
this.number = number;
this.safe = safe;
button.Text = "";
button.Click += button_Click;
}
public int getId()
{
return id;
}
public void setId(int i)
{
id = i;
}
public Button getButton()
{
return button;
}
public void setButton(Button b)
{
button = b;
}
public int getX()
{
return x;
}
public void setX(int i)
{
x = i;
}
public int getY()
{
return y;
}
public void setY(int i)
{
y = i;
}
public int getNumber()
{
return number;
}
public void setNumber(int i)
{
number = i;
}
public void addNumber()
{
number++;
}
public bool getSafe()
{
return safe;
}
public void setSafe(bool b)
{
safe = b;
}
private void button_Click(object sender, EventArgs e)
{
if (getSafe() == false) button.Text = getSafe().ToString();
else button.Text = getNumber().ToString();
if (getNumber() == 0) zeroReveal();
}
//---------------------------------------------------
// this is the method that reveals surrounding blocks
//---------------------------------------------------
private void zeroReveal()
{
foreach (Square s in list)
{
//revealing the blocks
s.getButton().Text = s.getNumber().ToString();
//call the same method if there's no mine
//this is the line that keeps giving me exception
if (s.getNumber() == 0) s.zeroReveal();
}
}
//-----------------------------------------------------
public List<Square> getList()
{
return list;
}
public void setList(List<Square> sl)
{
list = sl;
}
public void addList(Square s)
{
list.Add(s);
}
}

I am new to c# (or coding in general) and I guess this question is really stupid and confusing (I know I'm doing it a hard way)
This topic confuses many a new developer; don't stress out about it!
If there's no mines, same method will be applied to that block (calling the method recursively).
Recursive methods can be confusing but if you design them using the standard pattern, you will avoid SO exceptions. You have not designed yours using the standard pattern.
The standard pattern for successful recursive methods is:
Am I in a case that requires no recursion?
If yes, do the necessary computations to produce the desired effect and return. The problem is now solved.
If no, then we're going to recurse.
Break the current problem down into some number of smaller problems.
Solve each smaller problem by recursing.
Combine the solutions of the smaller problem to solve the current problem.
The problem is now solved, so return.
The most important thing about designing a recursive method is that each recursion must be solving a smaller problem, and the sequence of smaller problems must bottom out at a case that does not require recursion. If those two conditions are not met, then you will get a stack overflow.
Internalize that pattern, and every time you write a recursive method, actually write it out:
int Frob(int blah)
{
if (I am in the base case)
{
solve the base case
return the result
}
else
{
find smaller problems
solve them
combine their solutions
return the result
}
}
Fill in that template with your real code, and you will be much more likely to avoid stack overflows. I've been writing recursive methods for decades, and I still follow this pattern.
Now, in your example, what is the case that does not require recursion? There must be one, so write down what it is. Next, how will you guarantee that the recursion solves a smaller problem? That is often the hard step! Give it some thought.

The stack overflow is occurring because zeroReveal is recursively calling itself forever. To fix this we need to find ways where we do not need it to make further calls to itself.
The name of the method gives us a clue. If the square has already been revealed, then surely the method does not need to do anything, since it has already been revealed.
It looks like the button's Text property is an empty string if it has not yet been revealed. So change the foreach so that it doesn't process squares that have already been revealed:
foreach (Square s in list)
{
if (s.getButton().Text == ""))
{
// existing code in the foreach loop goes here
}
}

How to optimize recursive function for a graph for clearing and settlement

I have to make a module in an Insurance application that deals with clearing and settlement (I think this is the correct financial terminology) between insurance companies enroled in the system. Practically, the system must pair all the amounts that companies have to pay to one another, and only the unpaired (remaining) sums to be paid through the bank. For now there are about 30 companies in the system.
All the readings I did about clearing and settlement pointed me towards graphs and graphs theory (which I have studied in the highschool quite a long time ago).
For a system with 4 companies the graph would look like this:
where each company represents a node (N1 ... N4) and each weighted edge represents the amount that a company has to pay to the other. In my code, the nodes are int, representing the id's of the companies.
What I did so far... I created the graph (for test I used the Random generator for the amounts) and made a recursive function to calculate all posible cycles in the graph. Then I made another recursive function that takes all non-zero cycles starting with the longest path with maximum common sum to pair.
The algorithm seems valid in terms of final results, but for graphs bigger than 7-8 nodes it takes too long to complete. The problem is in the recursive function that creates the possible cycles in the graph. Here is my code:
static void Main(string[] args)
{
int nodes = 4;
try
{
nodes = Convert.ToInt32(args[0]);
}
catch { }
DateTime start = DateTime.Now;
Graph g = new Graph(nodes);
int step = 0;
double CompensatedAmount = 0;
double TotalCompensatedAmount = 0;
DateTime endGeneration = DateTime.Now;
Console.WriteLine("Graph generated in: " + (endGeneration - start).TotalSeconds + " seconds.");
Compensare.RunCompensation(false, g, step, CompensatedAmount, TotalCompensatedAmount, out CompensatedAmount, out TotalCompensatedAmount);
DateTime endCompensation = DateTime.Now;
Console.WriteLine("Graph compensated in: " + (endCompensation - endGeneration).TotalSeconds + " seconds.");
}
... and the main class:
public static class Compensare
{
public static void RunCompensation(bool exit, Graph g, int step, double prevCompensatedAmount, double prevTotalCompensatedAmount, out double CompensatedAmount, out double TotalCompensatedAmount)
{
step++;
CompensatedAmount = prevCompensatedAmount;
TotalCompensatedAmount = prevTotalCompensatedAmount;
if (!exit)
{
List<Cycle> orderedList = g.Cycles.OrderByDescending(x => x.CycleCompensatedAmount).ToList();
g.ListCycles(orderedList, "OrderedCycles" + step.ToString() + ".txt");
using (Graph clona = g.Clone())
{
int maxCycleIndex = clona.GetMaxCycleByCompensatedAmount();
double tmpCompensatedAmount = clona.Cycles[maxCycleIndex].CycleMin;
exit = tmpCompensatedAmount <= 0 ? true : false;
CompensatedAmount += tmpCompensatedAmount;
TotalCompensatedAmount += (tmpCompensatedAmount * clona.Cycles[maxCycleIndex].EdgesCount);
clona.CompensateCycle(maxCycleIndex);
clona.UpdateCycles();
Console.WriteLine(String.Format("{0} - edges: {4} - min: {3} - {1} - {2}\r\n", step, CompensatedAmount, TotalCompensatedAmount, tmpCompensatedAmount, clona.Cycles[maxCycleIndex].EdgesCount));
RunCompensation(exit, clona, step, CompensatedAmount, TotalCompensatedAmount, out CompensatedAmount, out TotalCompensatedAmount);
}
}
}
}
public class Edge
{
public int Start { get; set; }
public int End { get; set; }
public double Weight { get; set; }
public double InitialWeight {get;set;}
public Edge() { }
public Edge(int _start, int _end, double _weight)
{
this.Start = _start;
this.End = _end;
this.Weight = _weight;
this.InitialWeight = _weight;
}
}
public class Cycle
{
public List<Edge> Edges = new List<Edge>();
public double CycleWeight = 0;
public double CycleMin = 0;
public double CycleMax = 0;
public double CycleAverage = 0;
public double CycleCompensatedAmount = 0;
public int EdgesCount = 0;
public Cycle() { }
public Cycle(List<Edge> _edges)
{
this.Edges = new List<Edge>(_edges);
UpdateCycle();
}
public void UpdateCycle()
{
UpdateCycle(this);
}
public void UpdateCycle(Cycle c)
{
double sum = 0;
double min = c.Edges[0].Weight;
double max = c.Edges[0].Weight;
for(int i=0;i<c.Edges.Count;i++)
{
sum += c.Edges[i].Weight;
min = c.Edges[i].Weight < min ? c.Edges[i].Weight : min;
max = c.Edges[i].Weight > max ? c.Edges[i].Weight : max;
}
c.EdgesCount = c.Edges.Count;
c.CycleWeight = sum;
c.CycleMin = min;
c.CycleMax = max;
c.CycleAverage = sum / c.EdgesCount;
c.CycleCompensatedAmount = min * c.EdgesCount;
}
}
public class Graph : IDisposable
{
public List<int> Nodes = new List<int>();
public List<Edge> Edges = new List<Edge>();
public List<Cycle> Cycles = new List<Cycle>();
public int NodesCount { get; set; }
public Graph() { }
public Graph(int _nodes)
{
this.NodesCount = _nodes;
GenerateNodes();
GenerateEdges();
GenerateCycles();
}
private int FindNode(string _node)
{
for(int i = 0; i < this.Nodes.Count; i++)
{
if (this.Nodes[i].ToString() == _node)
return i;
}
return 0;
}
private int FindEdge(string[] _edge)
{
for(int i = 0; i < this.Edges.Count; i++)
{
if (this.Edges[i].Start.ToString() == _edge[0] && this.Edges[i].End.ToString() == _edge[1] && Convert.ToDouble(this.Edges[i].Weight) == Convert.ToDouble(_edge[2]))
return i;
}
return 0;
}
public Graph Clone()
{
Graph clona = new Graph();
clona.Nodes = new List<int>(this.Nodes);
clona.Edges = new List<Edge>(this.Edges);
clona.Cycles = new List<Cycle>(this.Cycles);
clona.NodesCount = this.NodesCount;
return clona;
}
public void CompensateCycle(int cycleIndex)
{
for(int i = 0; i < this.Cycles[cycleIndex].Edges.Count; i++)
{
this.Cycles[cycleIndex].Edges[i].Weight -= this.Cycles[cycleIndex].CycleMin;
}
}
public int GetMaxCycleByCompensatedAmount()
{
int toReturn = 0;
for (int i = 0; i < this.Cycles.Count; i++)
{
if (this.Cycles[i].CycleCompensatedAmount > this.Cycles[toReturn].CycleCompensatedAmount)
{
toReturn = i;
}
}
return toReturn;
}
public void GenerateNodes()
{
for (int i = 0; i < this.NodesCount; i++)
{
this.Nodes.Add(i + 1);
}
}
public void GenerateEdges()
{
Random r = new Random();
for(int i = 0; i < this.Nodes.Count; i++)
{
for(int j = 0; j < this.Nodes.Count; j++)
{
if(this.Nodes[i] != this.Nodes[j])
{
int _weight = r.Next(0, 500);
Edge e = new Edge(this.Nodes[i], this.Nodes[j], _weight);
this.Edges.Add(e);
}
}
}
}
public void GenerateCycles()
{
for(int i = 0; i < this.Edges.Count; i++)
{
FindCycles(new Cycle(new List<Edge>() { this.Edges[i] }));
}
this.UpdateCycles();
}
public void UpdateCycles()
{
for (int i = 0; i < this.Cycles.Count; i++)
{
this.Cycles[i].UpdateCycle();
}
}
private void FindCycles(Cycle path)
{
List<Edge> nextPossibleEdges = GetNextEdges(path.Edges[path.Edges.Count - 1].End);
for (int i = 0; i < nextPossibleEdges.Count; i++)
{
if (path.Edges.IndexOf(nextPossibleEdges[i]) < 0) // the edge shouldn't be already in the path
{
Cycle temporaryPath = new Cycle(path.Edges);
temporaryPath.Edges.Add(nextPossibleEdges[i]);
if (nextPossibleEdges[i].End == temporaryPath.Edges[0].Start) // end of path - valid cycle
{
if (!CycleExists(temporaryPath))
{
this.Cycles.Add(temporaryPath);
break;
}
}
else
{
FindCycles(temporaryPath);
}
}
}
}
private bool CycleExists(Cycle cycle)
{
bool toReturn = false;
if (this.Cycles.IndexOf(cycle) > -1) { toReturn = true; }
else
{
for (int i = 0; i < this.Cycles.Count; i++)
{
if (this.Cycles[i].Edges.Count == cycle.Edges.Count && !CompareEdges(this.Cycles[i].Edges[0], cycle.Edges[0]))
{
bool cycleExists = true;
for (int j = 0; j < cycle.Edges.Count; j++)
{
bool edgeExists = false; // if there is an edge not in the path, then the searched cycle is diferent from the current cycle and we can pas to the next iteration
for (int k = 0; k < this.Cycles[i].Edges.Count; k++)
{
if (CompareEdges(cycle.Edges[j], this.Cycles[i].Edges[k]))
{
edgeExists = true;
break;
}
}
if (!edgeExists)
{
cycleExists = false;
break;
}
}
if (cycleExists) // if we found an cycle with all edges equal to the searched cycle, then the cycle is not valid
{
toReturn = true;
break;
}
}
}
}
return toReturn;
}
private bool CompareEdges(Edge e1, Edge e2)
{
return (e1.Start == e2.Start && e1.End == e2.End && e1.Weight == e2.Weight);
}
private List<Edge> GetNextEdges(int endNode)
{
List<Edge> tmp = new List<Edge>();
for(int i = 0; i < this.Edges.Count; i++)
{
if(endNode == this.Edges[i].Start)
{
tmp.Add(this.Edges[i]);
}
}
return tmp;
}
#region IDisposable Support
private bool disposedValue = false; // To detect redundant calls
protected virtual void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
// TODO: dispose managed state (managed objects).
this.Nodes = null;
this.Edges = null;
this.Cycles = null;
this.NodesCount = 0;
}
// TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
// TODO: set large fields to null.
disposedValue = true;
}
}
// TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
// ~Graph() {
// // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
// Dispose(false);
// }
// This code added to correctly implement the disposable pattern.
public void Dispose()
{
// Do not change this code. Put cleanup code in Dispose(bool disposing) above.
Dispose(true);
// TODO: uncomment the following line if the finalizer is overridden above.
// GC.SuppressFinalize(this);
}
#endregion
}
I've found several articles/answers about graphs, both in Java and C# (including quickgraph), but they mainly focus on directed graphs (without cycles).
I have also read about tail call optimization, for recursion, but I don't know if/how to implement in my case.
I now there is a lot to grasp about this subject, but maybe someone had to deal with something similar and can either help me optimize the code (which as I said seems to do the job in the end), either point me to another direction to rethink the whole process.

I think you can massively simplify this.
All money is the same, so (using your example) N1 doesn't care whether it gets 350 from N2 and pays 150 to N2 and so on - N1 merely cares that overall it ends up 145 down (if I've done the arithmetic correctly). Similarly, each other N only cares about its overall position. So, summing the inflows and outflows at each node, we get:
Company Net position
N1 -145
N2 -65
N3 +195
N4 +15
So with someone to act as a central clearing house - the bank - simply arrange for N1 and N2 to pay the clearing house 145 and 65 respectively, and for N3 and N4 to receive 195 and 15 respectively from the clearing house. And everyone's happy.
I may have missed some aspect, of course, in which case I'm sure someone will point it out...

randomly do action with weighted values [closed]

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Closed 10 years ago.
lets say I have 5 outcomes
Console.WriteLine("1");
Console.WriteLine("2");
Console.WriteLine("3");
Console.WriteLine("4");
Console.WriteLine("5");
I want to randomly do one of the above actions using weights so lets say their weights start at 100.
it randomly prints 1 and lowers its weight by 5, making its weight 95.
so after this has done the weights in ascending order are (95, 100, 100, 100, 100) so all the 100 weights have a 5% chance of randomly being chosen over 95 but 95 still has a chance of being randomly picked but not as much as the others.
sample output:(console output)
1 (weight = 95)
3 (weight = 95)
1 (weight = 90)
5 (weight = 95)
1 (weight = 85)
2 (weight = 95)

No idea why you would be messing around with nested case statements.
Every time you need to generate a new random number, add up your weights.
Then use Random.Next(sumOfWeights).
Then compare your returned random number to the first weight, the sum of the first two weights, the sum of the first three weights, etc., until it is less than.
That's your selection. Then reduce that weight by 5.

Here is a simple code, If I understood well, what you need, you can use this, as a starting point:
class Program
{
static void Main(string[] args)
{
List<ActionWithChance> list = new List<ActionWithChance>()
{
new ActionWithChance("1", 100),
new ActionWithChance("2", 100),
new ActionWithChance("3", 100),
new ActionWithChance("4", 100),
new ActionWithChance("5", 100)
};
for (int i = 0; i < 10; i++)
{
RandomHandler.CreateIntervals(list);
RandomHandler.GetRandom(list);
}
}
}
static class RandomHandler
{
public static void CreateIntervals(List<ActionWithChance> list)
{
int currentBorderMin = 1;
int currentBorderMax = 0;
foreach (var actionWithChance in list)
{
actionWithChance.TempMin = currentBorderMin;
actionWithChance.TempMax = currentBorderMax
+ actionWithChance.Chance;
currentBorderMax = actionWithChance.TempMax;
currentBorderMin = currentBorderMax;
}
}
public static void GetRandom(List<ActionWithChance> list)
{
Thread.Sleep(20);
int allChance = list.Sum(i => i.Chance);
Random rand = new Random();
int nextValue = rand.Next(1, allChance + 1);
ActionWithChance selectedAction =
list.FirstOrDefault(i => i.TempMin <= nextValue && i.TempMax >= nextValue);
selectedAction.Chance = selectedAction.Chance > 5
? selectedAction.Chance - 5 : 100;
selectedAction.DoSomething();
}
}
class ActionWithChance
{
public string Name { get; set; }
public int Chance { get; set; }
public int TempMin { get; set; }
public int TempMax { get; set; }
public void DoSomething()
{
Console.WriteLine(Name);
}
public ActionWithChance(string name, int chance)
{
Name = name;
Chance = chance;
}
}

Another Approach:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections.Generic;
namespace RandomWeights
{
public class WeightedItem
{
public string Text { get; set; }
public int Weight { get; set; }
public WeightedItem(string text, int weight)
{
Text = text;
Weight = weight;
}
}
public class WeightedOutput
{
public static readonly int _decreaseIncrement = 5;
List<WeightedItem> items = new System.Collections.Generic.List<WeightedItem>();
public WeightedOutput()
{
//initialize the five items with weight = 100
for (int i = 1; i <= 5; i++)
items.Add(new WeightedItem(i.ToString(), 100));
for (int x = 0; x < 50; x++)
WriteSelected();
Console.ReadLine();
}
public void WriteSelected()
{
WeightedItem selectedItem = GetItem();
if (selectedItem != null)
Console.WriteLine(selectedItem.Text + ": " + selectedItem.Weight);
else
Console.WriteLine("All items have 0 probability of getting selected");
}
public WeightedItem GetItem()
{
int totalWeight = items.Sum(x=>x.Weight);
Random rnd = new Random((int)DateTime.Now.Ticks);
int random = rnd.Next(0, totalWeight);
WeightedItem selected = null;
foreach (var item in items)
{
if (random < item.Weight && item.Weight > 0)
{
//need a new item and not a reference to get the right weights
selected = new WeightedItem(item.Text, item.Weight);
//decrease item's weight
item.Weight -= _decreaseIncrement;
break;
}
random -= item.Weight;
}
return selected;
}
}
}

dice rolling in C# console application giving incorrect totals

I am writing dice roller program in C# console. I am giving two input
Enter the size of the dice and
Enter how times you want to play.
Suppose dice size is 6 and 10 times i have played.
Output is coming:
1 was rolled 2 times
2 was rolled 7 times
3 was rolled 8 times
4 was rolled 7 times
5 was rolled 4 times
6 was rolled 5 times
Total: 33 (its not fixed for every execution this no will be changed)
But my requirement was this total always should be number of playing times. Here I am playing 10 times so the total should be 10 not 33. It should happen for every new numbers... If I play 100 times sum or total should be 100 only not any other number. rest all will be remain same, in my programing not getting the expected sum. Please somebody modify it. Here is my code:
Dice.cs:
public class Dice
{
Int32 _DiceSize;
public Int32 _NoOfDice;
public Dice(Int32 dicesize)
{
this._DiceSize = dicesize;
}
public string Roll()
{
if (_DiceSize<= 0)
{
throw new ApplicationException("Dice Size cant be less than 0 or 0");
}
if (_NoOfDice <= 0)
{
throw new ApplicationException("No of dice cant be less than 0 or 0");
}
Random rnd = new Random();
Int32[] roll = new Int32[_DiceSize];
for (Int32 i = 0; i < _DiceSize; i++)
{
roll[i] = rnd.Next(1,_NoOfDice);
}
StringBuilder result = new StringBuilder();
Int32 Total = 0;
Console.WriteLine("Rolling.......");
for (Int32 i = 0; i < roll.Length; i++)
{
Total += roll[i];
result.AppendFormat("{0}:\t was rolled\t{1}\t times\n", i + 1, roll[i]);
}
result.AppendFormat("\t\t\t......\n");
result.AppendFormat("TOTAL: {0}", Total);
return result.ToString();
}
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter no of dice size");
int dicesize = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("How many times want to play");
int noofplay=Convert.ToInt32(Console.ReadLine());
Dice obj = new Dice(dicesize);
obj._NoOfDice = noofplay;
obj.Roll();
Console.WriteLine(obj.Roll());
Console.WriteLine("Press enter to exit");
Console.ReadKey();
}
}

It looks to me like you're getting the math backwards... shouldn't it be:
// to capture just the counts
int[] roll = new int[_DiceSize];
for (int i = 0; i < _NoOfDice; i++)
{
roll[rnd.Next(roll.Length)]++;
}
Or if you want the actual rolls:
// to capture individual rolls
int[] roll = new int[_NoOfDice];
for (int i = 0; i < _NoOfDice; i++)
{
roll[i] = rnd.Next(_DiceSize) + 1; // note upper bound is exclusive, so +1
}

You are creating a new Random instance on each iteration. This is not a good thing as it will affect the uniform distribution of results. Keep the Random instance in a field instead of creating a new one every time.
public class Dice {
private Random rnd = new Random();
// ... don't create a new random in `Roll` method. Use `rnd` directly.
}

First of all, the following for-loop is wrong:
for (Int32 i = 0; i < _DiceSize; i++)
{
roll[i] = rnd.Next(1,_NoOfDice);
}
Obviously you switched _DiceSize and _NoOfDice. The correct loop would look like
for (Int32 i = 0; i < _NoOfDice; i++)
{
roll[i] = rnd.Next(1,_DiceSize);
}
Because of that, the line
Int32[] roll = new Int32[_DiceSize];
has to be changed to
Int32[] roll = new Int32[_NoOfDice];
Maybe you should think about renaming these variables, so it's more clearly, which means what.
If you modify your code that way, you will mention that your analisys won't work that way you implemented it. Actually, what you are showing is the result of each throw, which is not what you want, if I understood you right.
UPDATE:
Sorry, I misunderstood you. You do want to show the result for every roll. So, why don't you just move the StringBuilder.AppendFormat to your "rolling-for-loop"?
UPDATE #2:
For me, the following Die-class works exactly the way you want it:
public class Die
{
private int maxValue;
private int numberOfRolls;
private Random random;
public Die(int maxValue, int numberOfRolls)
{
this.maxValue = maxValue;
this.numberOfRolls = numberOfRolls;
this.random = new Random();
}
public string Roll()
{
StringBuilder resultString = new StringBuilder();
for (int i = 0; i < this.numberOfRolls; i++)
{
resultString.AppendFormat("Roll #{0} - Result: {1}" + Environment.NewLine, i + 1, this.random.Next(1, maxValue + 1));
}
return resultString.ToString();
}
}
Hope I could help you.

This is the full code you have to use, according to Mehrdad and Marc Gravell.
Have fun.
public class Dice
{
private Random rnd = new Random();
Int32 _DiceSize;
public Int32 _NoOfDice;
public Dice(Int32 dicesize)
{
if (dicesize <= 0)
{
throw new ApplicationException("Dice Size cant be less than 0 or 0");
}
this._DiceSize = dicesize;
}
public string Roll()
{
if (_NoOfDice <= 0)
{
throw new ApplicationException("No of dice cant be less than 0 or 0");
}
// to capture just the counts
int[] roll = new int[_DiceSize];
for (int i = 0; i < _NoOfDice; i++)
{
roll[rnd.Next(roll.Length)]++;
}
StringBuilder result = new StringBuilder();
Int32 Total = 0;
Console.WriteLine("Rolling.......");
for (Int32 i = 0; i < roll.Length; i++)
{
Total += roll[i];
result.AppendFormat("{0}:\t was rolled\t{1}\t times\n", i + 1, roll[i]);
}
result.AppendFormat("\t\t\t......\n");
result.AppendFormat("TOTAL: {0}", Total);
return result.ToString();
}
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter no of dice size");
int dicesize = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("How many times want to play");
int noofplay = Convert.ToInt32(Console.ReadLine());
Dice obj = new Dice(dicesize);
obj._NoOfDice = noofplay;
Console.WriteLine(obj.Roll());
Console.WriteLine("Press enter to exit");
Console.ReadKey();
}
}