forked from KolibriOS/kolibrios
58 lines
1.3 KiB
Plaintext
58 lines
1.3 KiB
Plaintext
(*
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adapted to Oberon-07 by 0CodErr, KolibriOS team
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*)
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(*
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There are 100 doors in a row that are all initially closed.
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You make 100 passes by the doors.
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The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
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The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
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The third time, visit every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.
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What state are the doors in after the last pass? Which are open, which are closed?
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*)
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MODULE Doors;
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IMPORT In, Out, Console;
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CONST
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CLOSED = FALSE;
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OPEN = TRUE;
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TYPE
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List = ARRAY 101 OF BOOLEAN;
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VAR
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Doors: List;
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I, J: INTEGER;
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BEGIN
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Console.open;
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FOR I := 1 TO 100 DO
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FOR J := 1 TO 100 DO
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IF J MOD I = 0 THEN
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IF Doors[J] = CLOSED THEN
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Doors[J] := OPEN
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ELSE
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Doors[J] := CLOSED
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END
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END
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END
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END;
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FOR I := 1 TO 100 DO
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Out.Int(I, 3);
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Out.String(" is ");
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IF Doors[I] = CLOSED THEN
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Out.String("Closed.")
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ELSE
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Out.String("Open.")
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END;
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Out.Ln
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END;
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In.Ln;
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Console.exit(TRUE)
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END Doors. |