Helpmeplz

Hey guys there is some code that i need to finish my program, well at least the easy way, but I dont understand it. Im writting a tic tac toe program where the computer must never be beaten. This code is supposed to find how many x's there are in a row. But I dont know how to impliment it. Can any one help. Here it is.

Code:

row(i) = (i-1)/3+1

I'd have to see a little more code. For example, you could be using bits to hold the information or you could be using an array (or a 2d array). Perfect AI on a game like tic-tac-toe is impossible.

Code:

#include <iostream>
#include <string>

using namespace std;

bool endgame=false;

int rungame();
char board[9]={0,1,2,3,4,5,6,7,8};

void printboard();

	int main()
	{
		char x;

		while (!endgame)
		{

			cout << "Welcome. Would you like to play a game? " << endl;
			cout << "Press Y for yes and N for no. Followed by enter" << endl;
			cin >> x;

			if (x=='y')
				rungame();
			else
			if (x=='n')
				endgame=true;
		}

		return 0;
	}

	int rungame()
	{
		int move, x;

		board[0]=' ';
		board[1]=' ';
		board[2]=' ';
		board[3]=' ';
		board[4]=' ';
		board[5]=' ';
		board[6]=' ';
		board[7]=' ';
		board[8]=' ';

		for(x=1; x<=9; x++)
		{
			printboard();

			if ((x==1)||(x==3)||(x==5)||(x==7) || (x==9))
			{
				cout << "Please make a move between 1 and 9. Followed by enter." << endl;

				int move;
				cin >> move;

				if ((move==1)&&(board[0]!='x')&&(board[0]!='o'))
				{
					board[0]='x';
					cout << board[0] << " takes square 1" << endl;
				
				}else
				if ((move==2)&&(board[1]!='x')&&(board[1]!='o'))
				{
					board[1]='x';
					cout << board[1] << " takes square 2" << endl;
				
				}else
				if ((move==3)&&(board[2]!='x')&&(board[2]!='o'))
				{
					board[2]='x';
					cout << board[2] << " takes square 3" << endl;
			
				}else
				if ((move==4)&&(board[3]!='x')&&(board[3]!='o'))
				{
					board[3]='x';
					cout << board[3] << " takes square 4" << endl;
	
				}else
				if ((move==5)&&(board[4]!='x')&&(board[4]!='o'))
				{
					board[4]='x';
					cout << board[4] << " takes square 5" << endl;

				}else
				if ((move==6)&&(board[5]!='x')&&(board[5]!='o'))
				{
					board[5]='x';
					cout << board[5] << " takes square 6" << endl;
				
				}else
				if ((move==7)&&(board[6]!='x')&&(board[6]!='o'))
				{
					board[6]='x';
					cout << board[6] << " takes square 7" << endl;
		
				}else
				if ((move==8)&&(board[7]!='x')&&(board[7]!='o'))
				{
					board[7]='x';
					cout << board[7] << " takes square 8" << endl;

				}else
				if ((move==9)&&(board[8]!='x')&&(board[8]!='o'))
				{
					board[8]='x';
					cout << board[8] << " takes square 9" << endl;
			
				}

				if (move>10)
					cout << "Illegal move!" << endl;
				}else
					if ((x==2) || (x==4) || (x==6) || (x==8))
					{
						//Computers first move
						if (x==2)
						{
							if ((board[4]!='x')&&(board[4]!='o'))
							{
								board[4]='o';
							}else
								if ((board[0]!='x')&&(board[0]!='o'))
								{
									board[0]='o';
								}
						}

						//Block x
					}
			}
			cout << "CAT" << endl;
			return 0;
	}

	void printboard()
	{

		cout << board[0] << "|" << board[1] << "|" << board[2] << endl;
		cout << board[3] << "|" << board[4] << "|" << board[5] << endl;
		cout << board[6] << "|" << board[7] << "|" << board[8] << endl;

	}

There is my source. Im not trying to make a perfect tic tac toe AI, it juz can't loose.

Basically im trying to write a algorithm that will check all the differant squares for an 'x'. If there are 2 x's in a row, colum, or dialgnal then move to the square to block it. Thats all i need. After that I know how to program the win. Any ideas?

You can store the moves in a double subscripted array and check for certain patterns, and that's it, the only you have to do is to decide what patterns to look for.

Originally posted by master5001
<snip>Perfect AI on a game like tic-tac-toe is impossible.

Wow...that's saying quite a bit. I guess it'd depend on what you call 'perfect AI', but I'd sure hesitate a lot before I said it was impossible.

I'm curious too as to what you mean by "Perfect AI"....

The only way I know to do it is to just check each possible combination. There are eight ways to win. I suppose you could make an algorithm by checking each perimeter square and checking it's two immediate neighbors, one horizontal, one vertical, and only check the third if a match is made in the first check, and add a similar diagonal check at the corner, but that would be more work. Might be useful on a larger grid board, 10 x 10 or so.

I can see it being impossible to create an AI that always WINS - but I think it would be entirely possible to create one that always ties with the human player.

Tic-tac-toe is the sort of game where if both player pays attention and isn't a moron, the game will ALWAYS end up a tie.

Thats why its sort of a dumb game to play once you're older than 10... but if you're bored, hey who cares, right?

I agree...this was an assignment I had for one of my classes. Programming it so that the computer never loses isn't too hard; I doubt you could program it so that the computer always wins. Maybe that's the "perfect AI"?

That would have made an interesting end to 'War Games'.
"Sir, the computer just launched a full first strike package at the Russians!"
"My god, but why?"
"Well, the kid was playing Tic-Tac-Toe, trying to prove that with two smart opponents, in some games, there can be no winnerr; the computer decided in order for there to be a winner, one player has to not finish."

Originally posted by master5001
Perfect AI on a game like tic-tac-toe is impossible.

hahaha.

try working it out a little: its not to difficult to create a tic tac toe AI that will never lose.