Filosofos MONITOR

program Filosofos;

CONST NF = 4;
VAR k : INTEGER;

MONITOR Palillos;
EXPORT Coger, Dejar;
VAR palillos: ARRAY[1..NF] OF INTEGER;
comer: ARRAY [1..NF] OF CONDITION;
n: INTEGER;

PROCEDURE Coger(i: INTEGER);
BEGIN
IF palillos[i]<>2 THEN delay(comer[i]);
palillos[ (n MOD NF) + 1 ] := palillos [ (n MOD NF) + 1 ] - 1;
palillos[ ((n+NF-2) MOD NF) + 1 ] := palillos [ ((n+NF-2) MOD NF) + 1 ]-1;
writeln('Filosofo ',i,' empezó a comer');
END;

PROCEDURE Dejar(i:INTEGER);
BEGIN
writeln('Filosofo ',i,' dejó a comer');
palillos[ (n MOD NF) + 1 ] := palillos [ (n MOD NF) + 1 ] + 1;
palillos[ ((n+NF-2) MOD NF) + 1 ] := palillos [ ((n+NF-2) MOD NF) + 1 ] +1;
IF palillos[(n MOD NF) + 1] = 2 THEN resume(comer[(n MOD NF) + 1]);
IF palillos[((n+NF-2) MOD NF) + 1] = 2 THEN resume(comer[((n+NF-2) MOD NF) + 1]);
END;

BEGIN
FOR k:=1 TO NF DO Palillos[k] := 2;
END;

PROCESS TYPE Filosofos(n:INTEGER);
BEGIN
repeat
Palillos.Coger(n);
sleep(random(1));
Palillos.Dejar(n);
forever
END;

VAR filo : ARRAY[1..NF] OF Filosofos;

begin
COBEGIN
FOR k:=1 TO NF DO
filo[k](k);
COEND
end.