basic C++ question: - GoFuckYourself.com

04-05-2005, 08:25 PM

So I have this 2 dimensional Array (3X3)

and I want to make it so

"if there is an "X" in slot 2-2, return a "YES"

tried doing

if ( board[2][2] hahahaha 'X' )
{
cout << "Yes";
}
else
{
cout << "No";
}

and I keep on getting "No"s at every turn

can anybody help me out on this one?

what I am actually trying to do, is that it's a TIC TAC TOE game, and I need to stop the program once someone wins...

help me out yooo!!!

178340550

BuggyG · 04-05-2005, 08:57 PM

ah shit.. haven't done any C++ in over 10years

damn.. now I wanna know too
and I know it's a fuckin simple thing

skinnay · 04-05-2005, 09:20 PM

post the code somewhere where it wont go hahahaha

04-05-2005, 09:45 PM

Quote:

Originally Posted by skinnay

post the code somewhere where it wont go hahahaha

its just 2 "=" next to eachother

rickholio · 04-05-2005, 09:53 PM

Quote:

Originally Posted by bdjuf

So I have this 2 dimensional Array (3X3)

and I want to make it so

"if there is an "X" in slot 2-2, return a "YES"

tried doing

if ( board[2][2] hahahaha 'X' )
{
cout << "Yes";
}
else
{
cout << "No";
}

and I keep on getting "No"s at every turn

can anybody help me out on this one?

what I am actually trying to do, is that it's a TIC TAC TOE game, and I need to stop the program once someone wins...

help me out yooo!!!

178340550

Because [2][2] is actually referencing the 'bottom right' element of a 3x3 array. Arrays in C/C++ are referenced from 0. If you're trying to check the MIDDLE square, you're checking the wrong spot... and if you reference [3][3], you're overflowing and begging for a h4x0r 2 r0x0r j00r b0x0rz.

Try this:

Code:

  if(board[1][1]hahahaha'X') {       // Is there an X in the middle square?
    cout << "Yes";
  } else {
    cout << "No";
  }

BTW - The best way to make a TTT game is to have the program 'learn'. I did the same thing back in 80s on an atari 400... it's possible to make a damn-near unbeatable computerized opponent.

rickholio · 04-05-2005, 10:12 PM

A 'win' state checker:

Code:

char *checkwin(char board[2][2])  // Prototype might be a bit off, adjust accordingly ;)
{
  // Check horizontal
  for(int y=0;y<3;y++) {
    int xs, os;
    for(int x=0;x<3;x++) {
      xs += (board[x][y] = = 'X');
      os += (board[x][y] = = 'O');
    }
  }
  if(xs= =3) return("X Wins");
  if(os= =3) return("O Wins");

  // Check vertical
  for(int x=0;x<3;x++) {
    int xs, os;
    for(int y=0;y<3;y++) {
      xs += (board[x][y] = = 'X');
      os += (board[x][y] = = 'O');
    }
  }
  if(xs= =3) return("X Wins");
  if(os= =3) return("O Wins");

  // Check left-right diag
  for(int a=0,xs=0,os=0;a<3;a++) {
    xs += (board[a][a] = = 'X');
    os += (board[a][a] = = 'O');
  }
  if(xs= =3) return("X Wins");
  if(os= =3) return("O Wins");

  // Check right-left diag
  for(int a=0,xs=0,os=0;a<3;a++) {
    xs += (board[a][2-a] = = 'X');
    os += (board[a][2-a] = = 'O');
  }
  if(xs= =3) return("X Wins");
  if(os= =3) return("O Wins");

// No winnar.
  return;
}

There is almost certainly better ways of doing this (making a string of 3 characters in the array and matching that against a string of 'XXX' or 'OOO', for instance). This was just a 60 second slap together that'll do the job and demonstrate the logic cleanly.

wdsguy · 04-05-2005, 10:16 PM

Quote:

Originally Posted by bdjuf

So I have this 2 dimensional Array (3X3)

and I want to make it so

"if there is an "X" in slot 2-2, return a "YES"

tried doing

if ( board[2][2] hahahaha 'X' )
{
cout << "Yes";
}
else
{
cout << "No";
}

and I keep on getting "No"s at every turn

can anybody help me out on this one?

what I am actually trying to do, is that it's a TIC TAC TOE game, and I need to stop the program once someone wins...

help me out yooo!!!

178340550

Doing a assignment for cs class?

vas · 04-05-2005, 10:18 PM

use the min max algo, i coded a tic tac toe game for school a couple years ago using this algo, and it was undefeatable..

http://personal.vsnl.com/erwin/tictactoe.htm

nastyking · 04-05-2005, 11:31 PM

array element numbering starts with 0 not 1

Slacker · 04-06-2005, 12:01 AM

Nerds

just kidding

darnit · 04-06-2005, 12:41 AM

Nerds

04-06-2005, 02:04 PM

got it! thanx guys

now another question, how do I reset an array? make it all empty again?

tranza · 04-06-2005, 02:10 PM

Damn! I used to know C++, now I don't remember shit!

rickholio · 04-06-2005, 02:27 PM

Quote:

Originally Posted by bdjuf

got it! thanx guys

now another question, how do I reset an array? make it all empty again?

Assuming it's a contiguous area of memory and a simple array:

Code:

memset((void *)array_ptr, number_of_elements * sizeof(array_type), 0);

Alternately, you can request it be zeroed while allocating:

Code:

array_ptr = (array_type *)calloc(number_of_elements, sizeof(array_type));

You're doing c++, so you can always just destroy the old object and create a new one, which should set all values to their prototypes as well... if not, you can do the memset() thing in the object constructor.

HTH. HAND.

PS - If you malloc()'d the array originally, make sure you free() it before doing a new malloc(), otherwise you'll leak ram.

04-06-2005, 02:43 PM

everything works!!! thanx alot for your help guys

04-05-2005, 08:25 PM	#1
buddyjuf Guest Posts: n/a	basic C++ question: So I have this 2 dimensional Array (3X3) and I want to make it so "if there is an "X" in slot 2-2, return a "YES" tried doing if ( board[2][2] hahahaha 'X' ) { cout << "Yes"; } else { cout << "No"; } and I keep on getting "No"s at every turn can anybody help me out on this one? what I am actually trying to do, is that it's a TIC TAC TOE game, and I need to stop the program once someone wins... help me out yooo!!! 178340550

04-05-2005, 09:20 PM	#3
skinnay Confirmed User Join Date: Apr 2004 Location: NEW YORK CITY Posts: 2,274	post the code somewhere where it wont go hahahaha __________________ Make Real Green with ORGANIC SEO \| Blog post exchange \| Non-index page trades \| A-B C-D Trades [icq: 194-215-962] [mail: [email protected]]

04-05-2005, 10:18 PM	#8
vas Confirmed User Join Date: Dec 2003 Location: Toronto Posts: 562	use the min max algo, i coded a tic tac toe game for school a couple years ago using this algo, and it was undefeatable.. http://personal.vsnl.com/erwin/tictactoe.htm __________________ icq: 375956791

04-05-2005, 11:31 PM	#9
nastyking Join Date: Nov 2002 Posts: 2,174	array element numbering starts with 0 not 1 __________________

04-06-2005, 02:10 PM	#13
tranza ICQ: 197-556-237 Join Date: Jun 2003 Location: BRASIL !!! Posts: 57,559	Damn! I used to know C++, now I don't remember shit! __________________ I'm just a newbie.

04-05-2005, 08:57 PM	#2
BuggyG Confirmed User Join Date: Oct 2002 Location: Ottawa Posts: 4,179	ah shit.. haven't done any C++ in over 10years damn.. now I wanna know too and I know it's a fuckin simple thing

04-06-2005, 12:01 AM	#10
Slacker Confirmed User Join Date: Feb 2003 Location: Mostly the couch Posts: 331	Nerds just kidding

04-06-2005, 12:41 AM	#11
darnit Confirmed User Join Date: Jul 2001 Location: Teh Interweb Posts: 2,439	Nerds

04-06-2005, 02:04 PM	#12
buddyjuf Guest Posts: n/a	got it! thanx guys now another question, how do I reset an array? make it all empty again?

04-06-2005, 02:43 PM	#15
buddyjuf Guest Posts: n/a	everything works!!! thanx alot for your help guys