Mega Code Archive
Dining Philosopher
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/*
Quote from
C# and the .NET Framework
by Bob Powell
*/
using System;
using System.Threading;
public struct PhilosopherData {
public int PhilosopherId;
public Mutex RightChopStick;
public Mutex LeftChopStick;
public int AmountToEat;
public int TotalFood;
}
public class Philosopher : WorkerThread
{
public Philosopher( object data ) : base( data ) { }
protected override void Run( ) {
PhilosopherData pd = (PhilosopherData)Data;
Random r = new Random( pd.PhilosopherId );
Console.WriteLine("Philosopher {0} ready", pd.PhilosopherId );
WaitHandle[] chopSticks = new WaitHandle[] { pd.LeftChopStick, pd.RightChopStick };
while( pd.TotalFood > 0 ) {
//Get both chop sticks
WaitHandle.WaitAll( chopSticks );
Console.WriteLine("Philosopher {0} eating {1} of {2} food", pd.PhilosopherId, pd.AmountToEat, pd.TotalFood );
pd.TotalFood -= pd.AmountToEat;
Thread.Sleep( r.Next(1000,5000) );
//Release the chopsticks
Console.WriteLine("Philosopher {0} thinking", pd.PhilosopherId);
pd.RightChopStick.ReleaseMutex( );
pd.LeftChopStick.ReleaseMutex( );
//Think for a random time length
Thread.Sleep( r.Next(1000,5000) );
}
Console.WriteLine("Philosopher {0} finished", pd.PhilosopherId );
}
}
public class Restaurant {
public static void Main( ) {
Mutex[] chopSticks = new Mutex[5];
//init the chopSticks
for( int i = 0; i < 5; i++ )
chopSticks[i] = new Mutex( false );
//Create the Five Philosophers
for( int i = 0; i < 5; i++ ) {
PhilosopherData pd;
pd.PhilosopherId = i + 1;
pd.RightChopStick = chopSticks[ i - 1 >= 0 ? ( i - 1 ) : 4 ];
pd.LeftChopStick = chopSticks[i];
pd.AmountToEat = 5;
pd.TotalFood = 35;
Philosopher p = new Philosopher( pd );
p.Start( );
}
Console.ReadLine( );
}
}
public abstract class WorkerThread {
private object ThreadData;
private Thread thisThread;
//Properties
public object Data {
get { return ThreadData; }
set { ThreadData = value; }
}
public object IsAlive {
get { return thisThread == null ? false : thisThread.IsAlive; }
}
/// <summary>
/// Constructors
/// </summary>
public WorkerThread( object data ) {
this.ThreadData = data;
}
public WorkerThread( ) {
ThreadData = null;
}
/// <summary>
/// Public Methods
/// </summary>
/// <summary>
/// Start the worker thread
/// </summary>
public void Start( ) {
thisThread = new Thread( new ThreadStart( this.Run ) );
thisThread.Start();
}
/// <summary>
/// Stop the current thread. Abort causes
/// a ThreadAbortException to be raised within
/// the thread
/// </summary>
public void Stop( ) {
thisThread.Abort( );
while( thisThread.IsAlive ) ;
thisThread = null;
}
/// <summary>
/// To be implemented by derived threads
/// </summary>
protected abstract void Run( );
}
Philosopher 1 ready
Philosopher 1 eating 5 of 35 food
Philosopher 2 ready
Philosopher 3 ready
Philosopher 3 eating 5 of 35 food
Philosopher 4 ready
Philosopher 5 ready
Philosopher 1 thinking
Philosopher 5 eating 5 of 35 food
Philosopher 3 thinking
Philosopher 2 eating 5 of 35 food
Philosopher 5 thinking
Philosopher 4 eating 5 of 35 food
^CTerminate batch job (Y/N)? n
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