RosettaCodeData/Task/Dining-philosophers/BBC-BASIC/dining-philosophers.basic

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INSTALL @lib$+"TIMERLIB"
nSeats% = 5
DIM Name$(nSeats%-1), Fork%(nSeats%-1), tID%(nSeats%-1), Leftie%(nSeats%-1)
Name$() = "Aristotle", "Kant", "Spinoza", "Marx", "Russell"
Fork%() = TRUE : REM All forks are initially on the table
Leftie%(RND(nSeats%)-1) = TRUE : REM One philosopher is lefthanded
tID%(0) = FN_ontimer(10, PROCphilosopher0, 1)
tID%(1) = FN_ontimer(10, PROCphilosopher1, 1)
tID%(2) = FN_ontimer(10, PROCphilosopher2, 1)
tID%(3) = FN_ontimer(10, PROCphilosopher3, 1)
tID%(4) = FN_ontimer(10, PROCphilosopher4, 1)
ON CLOSE PROCcleanup : QUIT
ON ERROR PRINT REPORT$ : PROCcleanup : END
DEF PROCphilosopher0 : PROCtask(0) : ENDPROC
DEF PROCphilosopher1 : PROCtask(1) : ENDPROC
DEF PROCphilosopher2 : PROCtask(2) : ENDPROC
DEF PROCphilosopher3 : PROCtask(3) : ENDPROC
DEF PROCphilosopher4 : PROCtask(4) : ENDPROC
REPEAT
WAIT 0
UNTIL FALSE
END
DEF PROCtask(n%)
PRIVATE state%(), lh%(), rh%()
DIM state%(nSeats%-1), lh%(nSeats%-1), rh%(nSeats%-1)
REM States: 0 = waiting for forks, > 0 = eating, < 0 = left the room
CASE TRUE OF
WHEN state%(n%) < 0:
state%(n%) += 1 : REM Waiting to get hungry again
IF state%(n%) = 0 PRINT Name$(n%) " is hungry again"
WHEN state%(n%) > 0:
state%(n%) -= 1 : REM Eating
IF state%(n%) = 0 THEN
SWAP Fork%((n%-1+nSeats%) MOD nSeats%), lh%(n%)
SWAP Fork%((n% + 1) MOD nSeats%), rh%(n%)
state%(n%) = -RND(100)
PRINT Name$(n%) " is leaving the room"
ENDIF
WHEN state%(n%) = 0:
IF Leftie%(n%) THEN
IF NOT lh%(n%) SWAP Fork%((n%-1+nSeats%) MOD nSeats%), lh%(n%)
IF lh%(n%) IF NOT rh%(n%) SWAP Fork%((n% + 1) MOD nSeats%), rh%(n%)
ELSE
IF NOT rh%(n%) SWAP Fork%((n% + 1) MOD nSeats%), rh%(n%)
IF rh%(n%) IF NOT lh%(n%) SWAP Fork%((n%-1+nSeats%) MOD nSeats%), lh%(n%)
ENDIF
IF lh%(n%) AND rh%(n%) THEN
state%(n%) = RND(100)
PRINT Name$(n%) " is eating (" ; state%(n%) " ticks)"
ENDIF
ENDCASE
ENDPROC
DEF PROCcleanup
LOCAL I%
FOR I% = 0 TO nSeats%-1
PROC_killtimer(tID%(I%))
NEXT
ENDPROC