##tac tac toe game for maplev4
#Human plays first

tictactoe:=proc()
local i,place1,turn,ans;
global s1,s2,s3,s4,s5,s6,s7,s8,s9,stoop;
for i from 1 to 9 do s.i:=` `; od;
print(`Tic-tac-toe game for 2 players`);
print(`  `);
print(`Do you want to play tic-tac-toe? (Enter "Y" or "N" - no semicolon)`);
ans := readline(terminal); 
#print(`ans=`,ans,evalb(ans = ('Y') or ans = y)); 
if not(evalb(ans = ('Y') or ans = y)) then 
   print(`Thanks for playing tic-tac-toe.`);
   RETURN(); 
fi;
print(`You play "x" and the computer plays "o"`);
print(`Make your first move by entering a number`);
print(`1 through 9 as in the array below:`);
print(array(1..3,1..3,[[1,2,3],[4,5,6],[7,8,9]]));
print(` `);
for turn from 1 to 15 do
if evalb(isdraw()=`y`) then
    print(`Drawn game - thanks for playing tic-tac-toe with me`);
    break;
    RETURN();
fi;
 print(`Where do you want to play? (Enter "0", ..., "9" - "0" stops)`);
 place.turn := readline(terminal);
 ans:=parse(place.turn);
#print(turn,place.turn,ans,s.ans,whattype(place.turn),whattype(ans)); 
  if evalb(ans=0) then 
   print(`Thanks for playing tic-tac-toe.`);
   RETURN(); 
  fi;
 if (evalb(s.ans='o') or evalb(s.ans='x')) then
  print(`Try again at another place.`); 
  next;
 else s.ans:='x'; 
#print(`s.ans = `,s.ans);
 fi;
print(`Your move:`);
print(array(1..3,1..3,[[s.1,s.2,s.3],[s.4,s.5,s.6],[s.7,s.8,s.9]]));
nextmove();
if stoop=`Y` then 
#    print(`Thanks for playing tic-tac-toe.`);
   RETURN(); 
fi;
od;
##Lots more cases
end:

nextmove:=proc()
local i,j,s;
global stoop;
if ((s.1=`x` and s.5=`x` and s.9=`x`) or
(s.1=`x` and s.2=`x` and s.3=`x`) or
(s.1=`x` and s.4=`x` and s.7=`x`) or
(s.2=`x` and s.5=`x` and s.8=`x`) or
(s.3=`x` and s.5=`x` and s.7=`x`) or
(s.3=`x` and s.6=`x` and s.9=`x`) or
(s.7=`x` and s.8=`x` and s.9=`x`) or
(s.4=`x` and s.5=`x` and s.6=`x`)) then
  print(`You win. Thanks for playing tic-tac-toe.`);
  stoop:=`Y`;
  RETURN(stoop):
fi;
if ((s.1=`o` and s.5=`o` and s.9=`o`) or
(s.1=`o` and s.2=`o` and s.3=`o`) or
(s.1=`o` and s.4=`o` and s.7=`o`) or
(s.2=`o` and s.5=`o` and s.8=`o`) or
(s.3=`o` and s.5=`o` and s.7=`o`) or
(s.3=`o` and s.6=`o` and s.9=`o`) or
(s.7=`o` and s.8=`o` and s.9=`o`) or
(s.4=`o` and s.5=`o` and s.6=`o`)) then
  print(`Computer wins. Thanks for playing tic-tac-toe.`);
  RETURN():
fi;
##Computer wins in 1 move

###1-5-9
if (s.1=`o` and s.5=`o` and s.9=` `) then 
  s.9:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`o` and s.9=`o` and s.5=` `) then 
  s.5:=`o`; 
  printmove();
  RETURN():
fi;
if (s.5=`o` and s.9=`o` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;

###1-2-3
if (s.1=`o` and s.2=`o` and s.3=` `) then 
  s.3:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`o` and s.3=`o` and s.2=` `) then 
  s.2:=`o`; 
  printmove();
  RETURN():
fi;
if (s.2=`o` and s.3=`o` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;

###1-4-7
if (s.1=`o` and s.4=`o` and s.7=` `) then 
  s.7:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`o` and s.7=`o` and s.4=` `) then 
  s.4:=`o`; 
  printmove();
  RETURN():
fi;
if (s.7=`o` and s.4=`o` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;
##Lots more cases

###1-5-9
if (s.1=`x` and s.5=`x` and s.9=` `) then 
  s.9:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`x` and s.9=`x` and s.5=` `) then 
  s.5:=`o`; 
  printmove();
  RETURN():
fi;
if (s.9=`x` and s.5=`x` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;

###1-2-3
if (s.1=`x` and s.2=`x` and s.3=` `) then 
  s.3:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`x` and s.3=`x` and s.2=` `) then 
  s.2:=`o`; 
  printmove();
  RETURN():
fi;
if (s.3=`x` and s.2=`x` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;

###1-4-7
if (s.1=`x` and s.4=`x` and s.7=` `) then 
  s.7:=`o`; 
  printmove();
  RETURN():
fi;
if (s.1=`x` and s.7=`x` and s.4=` `) then 
  s.4:=`o`; 
  printmove();
  RETURN():
fi;
if (s.4=`x` and s.7=`x` and s.1=` `) then 
  s.1:=`o`; 
  printmove();
  RETURN():
fi;

###4-5-6
if (s.4=`x` and s.5=`x` and s.6=` `) then 
  s.6:=`o`; 
  printmove();
  RETURN():
fi;
if (s.4=`x` and s.6=`x` and s.5=` `) then 
  s.5:=`o`; 
  printmove();
  RETURN():
fi;
if (s.6=`x` and s.5=`x` and s.4=` `) then 
  s.4:=`o`; 
  printmove();
  RETURN():
fi;

###7-8-9
if (s.7=`x` and s.8=`x` and s.9=` `) then 
  s.9:=`o`; 
  printmove();
  RETURN():
fi;
if (s.7=`x` and s.9=`x` and s.8=` `) then 
  s.8:=`o`; 
  printmove();
  RETURN():
fi;
if (s.9=`x` and s.8=`x` and s.7=` `) then 
  s.7:=`o`; 
  printmove();
  RETURN():
fi;
### Lots more cases

##Make a "random" move:
if s.5=` ` then 
  s.5:=`o`; 
  printmove();
  RETURN():
fi;

for i from 1 to 9 do
 if evalb(s.i=` `) then 
  s.i:=`o`; 
  printmove();
  break;
  RETURN(): 
 fi;
od;

##Lots more cases
if isdraw=`y` then 
 print(`Drawn game - thanks for playing tic-tac-toe with me`);
 stoop:=`Y`;
 RETURN();
fi;
#RETURN([s.1,s.2,s.3,s.4,s.5,s.6,s.7,s.8,s.9]);
end:

printmove:=proc()
global stoop;
  print(`Computer's move:`);
  print(array(1..3,1..3,[[s.1,s.2,s.3],[s.4,s.5,s.6],[s.7,s.8,s.9]]));
# print(isdraw());
  if evalb(isdraw()=`y`) then 
    print(`Drawn game - thanks for playing tic-tac-toe with me`);
    stoop:=`Y`;
    RETURN();
  fi;
  print(`Your turn.`);
  RETURN():
end:

isdraw:=proc()
local i,draw;
draw:=`y`;
for i from 1 to 9 do
 if evalb(s.i=` `) then draw:=`n`; 
fi;
od;
RETURN(draw); 
end: