(**********************************************************
*	PART OF OTHELLO.PAS so see that file for details.
************************************************************)

 (* included file for OTHELLO *)
 
 PROCEDURE updatecrt(VAR oldstatus,newstatus: gamestatus);
 FORWARD;
 FUNCTION flipof(oldcolor: color): color;
 FORWARD;
 PROCEDURE makemove(VAR status: gamestatus; VAR move: movedesc; updateadjacent:
 BOOLEAN);
 FORWARD;
 
 SEGMENT PROCEDURE initgame;
 CONST
 backspace = 8;
 VAR
 x,y:         coordinate;
 direc:       direction;
    answer:      CHAR;
 h,l,h0,l0:   INTEGER; (*for testing whether clock is on*)
 
 PROCEDURE defineboard;
 BEGIN
 FOR x := 1 TO 8 DO  FOR y := 1 TO 8 DO  WITH board[x,y] DO BEGIN
 border := (x IN [1,8]) OR (y IN [1,8]);
 corner := (x IN [1,8]) AND (y IN [1,8]);
 incenter4by4 := (x IN [3..6]) AND (y IN [3..6]);
 diagnexttocorner := (x IN [2,7]) AND (y IN [2,7]);
 FOR direc := north TO nw  DO WITH adjacentsq[direc] DO BEGIN 
 CASE direc OF
 north: onboard := x>1;
 ne:    onboard := (x>1) AND (y<8);
 east:  onboard := y<8;
                                se:    onboard := (x<8) AND (y<8);
 south: onboard := x<8;
 sw:    onboard := (x<8) AND (y>1);
 west:  onboard := y>1;
 nw:    onboard := (x>1) AND (y>1);
 END; (*CASE*)
 IF onboard THEN BEGIN
 CASE direc OF
 north,ne,nw: row := x-1;
 east,west:   row := x;
 south,se,sw: row := x+1;
 END;
 CASE direc OF
 nw,west,sw:  col := y-1;
 north,south: col := y;
 ne,east,se:  col := y+1;
 END;
 END;
 END; (*FOR direc...WITH adjacentsq...*)
 specialbordersq := border AND (NOT corner) AND 
 ( (x IN [2,4,5,7]) OR (y IN [2,4,5,7]) );
 IF specialbordersq THEN BEGIN
 otherofpair.onboard := TRUE;
 between.onboard := TRUE;
 IF x IN [1,8] THEN BEGIN
 otherofpair.row := x;
 between.row := x;
 IF y IN [2,5] THEN BEGIN
 otherofpair.col := y+2;
 between.col := y+1;
 END
 ELSE BEGIN
 otherofpair.col := y-2;
 between.col := y-1;
 END;
 END
 ELSE BEGIN
 otherofpair.col := y;
 between.col := y;
 IF x IN [2,5] THEN BEGIN
 otherofpair.row := x+2;
 between.row := x+1;
 END
 ELSE BEGIN
          otherofpair.row := x-2;
 between.row := x-1;
 END;
 END;
 END; (*IF specialbordersq...*)
 END; (*FOR x:= ... FOR y:= ... WITH board[x,y]...*)
 END; (*defineboard*)
 
 PROCEDURE showemptyboard;
 CONST
 vertdivs = '|     |     |     |     |     |     |     |     |';
 horzdivs = '|-----|-----|-----|-----|-----|-----|-----|-----|';
 colnames = '   A     B     C     D     E     F     G     H   ';
    blanks   = '                              ';
 VAR
 gamerow :    coordinate;
 BEGIN
 GOTOXY(0,0);
 FOR gamerow := 1 TO 8 DO BEGIN
 IF gamerow>1 THEN (* "IF" because no room for topmost border line *)
 writeln(blanks,horzdivs);
 writeln(blanks:29,gamerow,vertdivs);
 writeln(blanks,vertdivs);
 END;
 write(blanks,colnames);
 GOTOXY(4,0);
 WRITELN('Score');
 WRITELN('-----------');
 WRITELN(CHR(whiteascii),'/White:');
 WRITELN(CHR(blackascii),'/Black:');
 END; (*showemptyboard*)
 
    PROCEDURE instructions;
 VAR
 i: INTEGER;
 PROCEDURE page1;
 BEGIN
                                    WRITELN('A move consists of placing  ');
 WRITELN('one of your pieces on an    ');
 WRITELN('unoccupied square which is  ');
 WRITELN('adjacent (vertically, hori- ');
 WRITELN('zontally, or diagonally) to ');
 WRITELN('a square occupied by your   ');
 WRITELN('opponent so that a straight ');
 WRITELN('line starting at your piece ');
 WRITELN('and continuing in the direc-');
 WRITELN('tion of the adjacent oppon- ');
 WRITELN('ent hits one of your other  ');
 WRITELN('pieces before hitting an un-');
 WRITELN('occupied square.  All of the');
 WRITELN('opponent''s pieces which that');
 WRITELN('line crosses are converted  ');
 WRITELN('to become your pieces.  Thus');
 WRITELN('each move "flips" at least  ');
 WRITELN('one opposing piece.         ');
 WRITE  (' (Tap space bar for more...)');
    END; (*page1*)
 PROCEDURE page2;
 BEGIN
 WRITELN('Example:  a legal move for  ');
 WRITELN('white on the first play     ');
 WRITELN('would be 3E, 4F, 6D, or 5C. ');
                               WRITELN('To make a move at, e.g., 3E ');
 WRITELN('you may type any of: 3E, 3e,');
 WRITELN('E3, or e3.                  ');
 WRITELN('If you have no legal move,  ');
 WRITELN('you must pass.  The object  ');
 WRITELN('of the game is to end up    ');
 WRITELN('occupying more squares than ');
 WRITELN('does your opponent.         ');
 WRITELN('Hints on strategy:  Usually ');
 WRITELN('the board position of a move');
 WRITELN('is more important than the  ');
 WRITELN('number of pieces it "flips".');
 WRITELN('Try to occupy the borders   ');
 WRITELN('(especially corners!) and   ');
 WRITELN('avoid giving them to your   ');
 WRITE  ('opponent. (Tap space bar...)');
    END; (*page2*)
 BEGIN (*instructions*)
 GOTOXY(0,5);
 WRITE('Want instructions? (y/n): ');
 READ(answer);
 IF NOT (answer IN ['N','n']) THEN BEGIN
 GOTOXY(0,5);
 page1;
 READ(answer);
 GOTOXY(0,5);
 page2;
 READ(answer);
 GOTOXY(0,5);
 FOR i := 5 TO 22 DO
 WRITELN(spaces);
 WRITE(spaces);
 END
 ELSE BEGIN
        GOTOXY(0,5);
 WRITE(spaces);
 END;
 END; (*instructions*)
 
 BEGIN (*initgame*)
 lastchange := 0;
 TIME(h0,l0);
 defineboard;
 FOR direc := north TO NW DO
 IF odd(ORD(direc)) THEN
       opposdir[direc] := pred(direc)
 ELSE
 opposdir[direc] := succ(direc);
 TIME(h,l);
 IF (h=h0) AND (l=l0) THEN BEGIN
 GOTOXY(20,11);
 WRITE('Please turn on the clock.');
 WHILE l=l0 DO
 TIME(h,l);
 END;
 showemptyboard;
 WITH status DO BEGIN
 score[white] := 0;
 score[black] := 0;
 FOR x := 1 TO 8 DO  FOR y := 1 TO 8 DO WITH boardstatus[x,y] DO BEGIN
    occupied := FALSE;
    adjacentpieces[white] := [];
 adjacentpieces[black] := [];
 END;
 END;
 crtstatus := status;
 move.dirsflipped := [];
 move.points := 0;
 WITH status DO BEGIN
 FOR x := 4 TO 5 DO  FOR y := 4 TO 5 DO BEGIN
 move.moveloc.row := x;
 move.moveloc.col := y;
 IF x=y THEN
 nextmover := white
 ELSE
 nextmover := black;
 makemove(status,move,TRUE);
 updatecrt(crtstatus,status);
       crtstatus := status;
              END; (*FOR...FOR...*)
 nextmover := white;
 END; (*WITH status...*)
 instructions;
 GOTOXY(0,6);
 WRITELN('White goes first -- Which');
 WRITELN('color do you want to play:');
 REPEAT
 GOTOXY(3,8);
    WRITE('W)hite or B)lack?  ',CHR(backspace));
    READ(answer);
 UNTIL answer IN ['W','w','B','b'];
 IF answer IN ['W','w'] THEN
 usercolor := white
 ELSE 
 usercolor := black;
 GOTOXY (0,6);
 WRITELN(spaces); WRITELN(spaces); WRITELN(spaces);
 colorword[white] := 'white';
 colorword[black] := 'black';
 END; (*initgame*)