phamster.tex

数据挖掘中de一个算法 hamster的实例

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{-----------------------------------------------------------------------
  File    : control.p
  Contents: hamster control program
  Author  : Christian Borgelt
  History : 24.03.1999 file created from file control.c
-----------------------------------------------------------------------}
UNIT control;
INTERFACE
USES hamster;

{-----------------------------------------------------------------------
  Function Prototype
-----------------------------------------------------------------------}
PROCEDURE hms_ctrl (hms : HAMSTER);

{-----------------------------------------------------------------------
  Hamster Control Function
-----------------------------------------------------------------------}
IMPLEMENTATION

PROCEDURE hms_ctrl (hms : HAMSTER);
VAR x, y    : INTEGER;          { coordinates of current field }
    movecnt : INTEGER;          { number of moves made }
    turn    : INTEGER;          { turn direction (HMS_POS/HMS_NEG) }
    d       : INTEGER;          { dummy for return values }
BEGIN                           { --- hamster control function }
  movecnt := 0;                 { initialize the move counter }
  WHILE (movecnt < 50) DO BEGIN { make 50 (field to field) moves }
    hms_pos(hms, x, y);         { get current position in maze }
    IF (x = 0) AND (y = 0)      { if we are at home (initial position) }
    THEN d := hms_drop(hms, HC_MAXLOAD)   { drop all the corn we have }
    ELSE IF (hms_corn(hms) > 0) { if there is corn on the field, take }
    THEN d := hms_take(hms, HC_MAXLOAD);    { as much as we can carry }
    IF (hms_look(hms) = HC_WALL)
    OR_ELSE (Random(4) <= 0)    { if the way is blocked }
    THEN BEGIN                  { or just because its funny, }
      IF (Random(2) <= 0)       { choose a random turn direction }
      THEN turn := HC_POS ELSE turn := HC_NEG;
      REPEAT hms_turn(hms,turn);{ turn hamster in random direction }
      UNTIL (hms_look(hms) <> HC_WALL);
    END;	                { until no wall blocks the way }
     d := hms_move(hms);        { move the hamster forward }
    movecnt := movecnt +1;      { and count the move made }
  END;
END;  { hms_ctrl() }

{----------------------------------------------------------------------}
END.
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