Task: Dining philosophers








VB: 




Public Const HOLDON = False
Public Const DIJKSTRASOLUTION = True
Public Const X = 10 
Public Const GETS = 0
Public Const PUTS = 1
Public Const EATS = 2
Public Const THKS = 5
Public Const FRSTFORK = 0
Public Const SCNDFORK = 1
Public Const SPAGHETI = 0
Public Const UNIVERSE = 1
Public Const MAXCOUNT = 100000
Public Const PHILOSOPHERS = 5
Public semaphore(PHILOSOPHERS - 1) As Integer
Public positi0n(1, PHILOSOPHERS - 1) As Integer
Public programcounter(PHILOSOPHERS - 1) As Long
Public statistics(PHILOSOPHERS - 1, 5, 1) As Long
Public names As Variant
Private Sub init()
    names = [{"Aquinas","Babbage","Carroll","Derrida","Erasmus"}]
    For j = 0 To PHILOSOPHERS - 2
        positi0n(0, j) = j + 1 
        positi0n(1, j) = j     
    Next j
    If DIJKSTRASOLUTION Then
        positi0n(0, PHILOSOPHERS - 1) = j 
        positi0n(1, PHILOSOPHERS - 1) = 0 
    Else
        positi0n(0, PHILOSOPHERS - 1) = 0 
        positi0n(1, PHILOSOPHERS - 1) = j 
    End If
End Sub
Private Sub philosopher(subject As Integer, verb As Integer, objekt As Integer)
    statistics(subject, verb, objekt) = statistics(subject, verb, objekt) + 1
    If verb < 2 Then
        If semaphore(positi0n(objekt, subject)) <> verb Then
            If Not HOLDON Then
                
                
                semaphore(positi0n(FRSTFORK, subject)) = 1 - objekt
                
                programcounter(subject) = 0
            End If
        Else
            
            semaphore(positi0n(objekt, subject)) = 1 - verb
            programcounter(subject) = (programcounter(subject) + 1) Mod 6
        End If
    Else
        
        
        programcounter(subject) = IIf(X * Rnd > 1, verb, verb + 1) Mod 6
    End If
End Sub
Private Sub dine()
    Dim ph As Integer
    Do While TC < MAXCOUNT
        For ph = 0 To PHILOSOPHERS - 1
            Select Case programcounter(ph)
                Case 0: philosopher ph, GETS, FRSTFORK
                Case 1: philosopher ph, GETS, SCNDFORK
                Case 2: philosopher ph, EATS, SPAGHETI
                Case 3: philosopher ph, PUTS, FRSTFORK
                Case 4: philosopher ph, PUTS, SCNDFORK
                Case 5: philosopher ph, THKS, UNIVERSE
            End Select
            TC = TC + 1
        Next ph
    Loop
End Sub
Private Sub show()
    Debug.Print "Stats", "Gets", "Gets", "Eats", "Puts", "Puts", "Thinks"
    Debug.Print "", "First", "Second", "Spag-", "First", "Second", "About"
    Debug.Print "", "Fork", "Fork", "hetti", "Fork", "Fork", "Universe"
    For subject = 0 To PHILOSOPHERS - 1
        Debug.Print names(subject + 1),
        For objekt = 0 To 1
            Debug.Print statistics(subject, GETS, objekt),
        Next objekt
        Debug.Print statistics(subject, EATS, SPAGHETI),
        For objekt = 0 To 1
            Debug.Print statistics(subject, PUTS, objekt),
        Next objekt
        Debug.Print statistics(subject, THKS, UNIVERSE)
    Next subject
End Sub
Public Sub main()
    init
    dine
    show
End Sub




Ada: with Ada.Numerics.Float_Random;  use Ada.Numerics.Float_Random;
with Ada.Text_IO;                use Ada.Text_IO;

with Synchronization.Generic_Mutexes_Array;

procedure Test_Dining_Philosophers is
   type Philosopher is (Aristotle, Kant, Spinoza, Marx, Russel);
   package Fork_Arrays is new Synchronization.Generic_Mutexes_Array (Philosopher);
   use Fork_Arrays;

   Life_Span : constant := 20;    
   Forks : aliased Mutexes_Array; 
   
   function Left_Of (Fork : Philosopher) return Philosopher is
   begin
      if Fork = Philosopher'First then
         return Philosopher'Last;
      else
         return Philosopher'Pred (Fork);
      end if;
   end Left_Of;

   task type Person (ID : Philosopher);
   task body Person is
      Cutlery : aliased Mutexes_Set := ID or Left_Of (ID);
      Dice    : Generator;
   begin
      Reset (Dice);
      for Life_Cycle in 1..Life_Span loop
         Put_Line (Philosopher'Image (ID) & " is thinking");
         delay Duration (Random (Dice) * 0.100);
         Put_Line (Philosopher'Image (ID) & " is hungry");
         declare
            Lock : Set_Holder (Forks'Access, Cutlery'Access);
         begin
            Put_Line (Philosopher'Image (ID) & " is eating");
            delay Duration (Random (Dice) * 0.100);
         end;
      end loop;
      Put_Line (Philosopher'Image (ID) & " is leaving");
   end Person;

   Ph_1 : Person (Aristotle); 
   Ph_2 : Person (Kant);
   Ph_3 : Person (Spinoza);
   Ph_4 : Person (Marx);
   Ph_5 : Person (Russel);
begin
   null; 
end Test_Dining_Philosophers;