Solved

Running Debugged vs. Non-Debugged

Posted on 2004-08-28
2
210 Views
Last Modified: 2010-04-15
Hi,
I have a program that simulates a game many times and returns the percent of the time that each team won (8 teams).  I believe I have all the logics correct, but I'm finding some odd results.  When I run the program stepping through the lines (in debug mode obviously), it distributes the wins correctly.  However, when I simply run the program through for 100 trials, one team will win all 100 times.  And then if I run it again, another team will win 100 times.  Then again, and team 1 will win 84 times and team 2 will win 16 times and the other 6 teams won't win at all.  Now if I run the program through a million trials, it seems to distribute nicely.  I'm really confused as to why this would ever happen.  My logic is correct since as I said before, running the program debugged works fine.  This is C# dot net console program btw.

Here's my code:
using System;

namespace Project1
{
      class Class1
      {
            [STAThread]
            public static void Main(string[] args)
            {
                  int gameWinner;
                  double percentWon;
                  int[] teamGames = new int[8];
                  
                  for (int xx = 1; xx <= 100; xx++)
                  {
                        gameWinner = Class1.RunGame();
                        teamGames[gameWinner]++;
                  }

                  for (int yy = 1; yy <= 8; yy++)
                  {
                        percentWon = (teamGames[yy - 1]/100.000);
                        Console.WriteLine("Team " + yy + " = " + percentWon);
                  }
            }
            
            public static int RunGame()
            {
                  int team1, team2, teamondeck, pointmod, winner;
                  int[] teamWins = new int[8];

                  team1 = 1;
                  team2 = 2;
                  teamondeck = 3;
                  pointmod = 1;
                  Random r = new Random();
                  
                  while (true)
                  {
                        if (r.NextDouble() >= .5)
                        {
                              teamWins[team1 - 1] = teamWins[team1 - 1] + pointmod;
                              if (teamWins[team1 - 1] >= 7)
                              {
                                    winner = team1 - 1;
                                    break;
                              }
                              team2 = teamondeck;
                              teamondeck++;
                        }
                        else
                        {
                              teamWins[team2 - 1] = teamWins[team2 - 1] + pointmod;
                              if (teamWins[team2 - 1] >= 7)
                              {
                                    winner = team2 - 1;
                                    break;
                              }
                              team1 = team2;
                              team2 = teamondeck;
                              teamondeck++;
                        }
                        if (teamondeck > 8)
                        {
                              teamondeck = 1;
                              pointmod = 2;
                        }
                  }
                  return winner;
            }
      }
}


I'd appreciate any help.  Thanks!!
0
Comment
Question by:schwarz2
2 Comments
 
LVL 3

Accepted Solution

by:
GrumbleBot earned 125 total points
ID: 11925787
I found by making the variable r a global variable your program works correctly. Not sure if I can explain why it doesn't work the way that you have it. But if i basically set up a random numbe rin a fuction and fill a listbox continually I get the same number for many consecutive values then it changes and repeats those many times , on and on.

Well here is your code modified and it seems to work now.

using System;

namespace Project1
{
      class Class1
      {
            static Random r;

            [STAThread]
            public static void Main(string[] args)
            {
                  int gameWinner;
                  double percentWon;
                  int[] teamGames = new int[8];
                  r = new Random(); //((int)DateTime.Now.Ticks)
               
                  for (int xx = 1; xx <= 100; xx++)
                  {
                        gameWinner = Class1.RunGame();
                        teamGames[gameWinner]++;
                  }

                  for (int yy = 1; yy <= 8; yy++)
                  {
                        percentWon = (teamGames[yy - 1]/100.000);
                        Console.WriteLine("Team " + yy + " = " + percentWon);
                  }
                  
            }
         
            public static int RunGame()
            {
                  int team1, team2, teamondeck, pointmod, winner;
                  int[] teamWins = new int[8];

                  team1 = 1;
                  team2 = 2;
                  teamondeck = 3;
                  pointmod = 1;
               
                  while (true)
                  {
                        if (r.NextDouble() >= .5)
                        {
                              teamWins[team1 - 1] = teamWins[team1 - 1] + pointmod;
                              if (teamWins[team1 - 1] >= 7)
                              {
                                    winner = team1 - 1;
                                    break;
                              }
                              team2 = teamondeck;
                              teamondeck++;
                        }
                        else
                        {
                              teamWins[team2 - 1] = teamWins[team2 - 1] + pointmod;
                              if (teamWins[team2 - 1] >= 7)
                              {
                                    winner = team2 - 1;
                                    break;
                              }
                              team1 = team2;
                              team2 = teamondeck;
                              teamondeck++;
                        }
                        if (teamondeck > 8)
                        {
                              teamondeck = 1;
                              pointmod = 2;
                        }
                  }
                  return winner;
            }
      }
}

Hope this helps.

Good luck
0
 

Author Comment

by:schwarz2
ID: 11926547
Excellent, GrumbleBot!!  This was driving me crazy .. I guess C# doesn't re-seed the random variable when it's re-created.  Very strange, but I'm glad you caught it.  Thanks millions.
0

Featured Post

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Video Player 12 27
how to double quote a string for an inline sql statement. 8 73
IEnumerable<T> to a List<T> 8 37
need to convert function to c# 5 29
This article introduced a TextBox that supports transparent background.   Introduction TextBox is the most widely used control component in GUI design. Most GUI controls do not support transparent background and more or less do not have the…
Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online. The email signature template has been downloaded from: www.mail-signatures…
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question