'''
''  TIC-TAC-TOE
''
''  SmallBASIC 0.5.6 example
''  (PEN/MOUSE use example)
''

DIM MAT(9), PW(8), ST(3)

LABEL RESTART
FOR I=1 TO 9
  MAT(I)=0
NEXT

cls
? cat(1);"Tic-Tac-Toe";cat(0)
? chr$(27)+"[92m"
? "A SmallBASIC example"

at 0,130
? "X=USER, O=CPU" 
? "Are you want to play first"; 
INPUT sel

WINNER=0
IF UCASE$(LEFT$(sel,1))="Y" THEN
  PLAYER=-1
ELSE 
  PLAYER=1
FI

'' start
WHILE 1
  IF PLAYER=-1 
    GOSUB DISPLAY
    GOSUB USER
  ELSE
    GOSUB COMPUTER
  FI
  GOSUB CHECK
  PLAYER=-PLAYER
  IF WINNER THEN 1000
WEND

1000 '' EXIT LOOP
GOSUB DISPLAY
at 0,130:? cat(1);
IF WINNER=-1
  ? "YOU WIN!"
ELIF WINNER=1
  ? "I WIN!"
ELSE
  ? "TIE!"
FI
? cat(0)
at 0,148
INPUT "PLAY AGAIN?",SEL
IF UCASE$(LEFT$(SEL,1))="Y" THEN GOTO RESTART
END

''===================
LABEL USER
pen on
while 1
  if pen(0)
    x=pen(4):y=pen(5)
    p=int((x-20)/40)+1
    if y>80
      p=p+6
    elif y>40
      p=p+3
    fi
    if mat(p)=0 then 3000 else beep
  fi
wend
3000 '' exit while
pen off
MAT(P)=PLAYER
RETURN

''===================
LABEL COMPUTER
PLAYER=1
GOSUB Check

'' WINNER MOVE
FOR I=1 TO 8
  IF PW(I)=2
    GOSUB SELPOS
    GOTO CCFIN
  FI
NEXT

'' DEFENCE MOVE
FOR I=1 TO 8
  IF PW(I)=-2
    GOSUB SELPOS
    GOTO CCFIN
  FI
NEXT
''
'' SIMPLE MOVE - THIS LETS USER TO WIN
'' BECAUSE IT DOES NOT CALCULATE THE
'' FREE CELLS
''
IF MAT(5)=0
  P=5
ELSE
  FOR I=1 TO 9
    IF MAT(I)=0 THEN
      P=I
      GOTO CCFIN
    FI
  NEXT
FI

LABEL CCFIN
MAT(P)=PLAYER
RETURN

''===================
LABEL SELPOS
IF I < 4
  ST(1)=(I-1)*3+1
  ST(2)=(I-1)*3+2
  ST(3)=(I-1)*3+3
ELIF I < 7
  ST(1)=(I-3)
  ST(2)=(I-3)+3
  ST(3)=(I-3)+6
ELIF I=7
  ST(1)=1:ST(2)=5:ST(3)=9
ELSE
  ST(1)=3:ST(2)=5:ST(3)=7
FI

IF MAT(ST(1))=0
  P=ST(1)
ELIF MAT(ST(2))=0
  P=ST(2)
ELSE
  P=ST(3)
FI
RETURN

''===================
LABEL Check
FOR i=1 TO 3
  PW(i)=MAT((i-1)*3+1)
  PW(i)=PW(i)+MAT((i-1)*3+2)
  PW(i)=PW(i)+MAT((i-1)*3+3)
  PW(i+3)=MAT(i)+MAT(i+3)+MAT(i+6)
NEXT
PW(7)=MAT(1)+MAT(5)+MAT(9)
PW(8)=MAT(3)+MAT(5)+MAT(7)
FOR i=1 TO 8
  IF PW(i)=-3 THEN WINNER=-1
  IF PW(i)= 3 THEN WINNER=1
NEXT

IF WINNER=0 THEN 
  CNT=0
  FOR i=1 TO 9
    IF MAT(i) THEN CNT=CNT+1
  NEXT
  IF CNT=9 THEN WINNER=999
FI
RETURN 

''===================
LABEL DISPLAY
cls
rect 0,0,160,140 color 15 filled
line 20,40,140,40
line 20,80,140,80
line 60,0,60,120
line 100,0,100,120
FOR N=1 TO 9 STEP 3
  y=int(n/3)*40+20
  FOR O=0 TO 2
    x=(o+1)*40
    IF MAT(O+N)=1
      circle x,y,10
    ELIF MAT(O+N)=-1
      line x-10,y-10,x+10,y+10
      line x+10,y-10,x-10,y+10
    FI
  NEXT
NEXT
RETURN



'