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tic tac toe question

nukacola (5)
Hi everyone!

I'm nearing completion with this tic tac toe program, except I need a little help.

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#include <iostream>

using namespace std;

const int R=3;
const int C=3;
char space[R][C] = {'1','2','3','4','5','6','7','8','9'};

int main() {

	bool win;
	int count = 0;
	int currentPlayer;
	int xPlayer = 1;
	int oPlayer = 2;	
	
	void displayBoard();
	int makeMove(int, int, int);
	int checkWin(bool);
	int displayWin(bool);
	int newGame(int);

	currentPlayer = xPlayer;
	
	cout << "\nWelcome to my Tic Tac Toe game! \n";

	do{
		cout << "It is player " << currentPlayer << "'s turn.\n";

		displayBoard();			
		makeMove(currentPlayer, xPlayer, oPlayer);
		checkWin(win);
		displayWin(win);

		if (currentPlayer == xPlayer){
			currentPlayer = oPlayer;
		}else
		if(currentPlayer == oPlayer){
			currentPlayer = xPlayer;
		}
		count++;		

		if(win == true){
			count = 8;
		}

	}while(count <=8);

	displayBoard();
	
}

void displayBoard(){

	for(int i=0; i<3; i++){
		for(int j=0; j<3; j++){
			cout << space[i][j];
			if(j<2)
				cout << " | ";
		}
		cout << endl;
		if(i<2){
			cout << "_________" << endl;
		}
	}

}

int makeMove(int currentPlayer, int xPlayer, int oPlayer) {

	int choice;
	int r, c;
	char playerSymbol;

	if(currentPlayer == xPlayer){
		playerSymbol = 'X';
	}else
	if(currentPlayer == oPlayer){
		playerSymbol = 'O';
	}
	
		cout << "Player " << currentPlayer << "'s move:\n";
		cin >> choice;

		if(choice == 1 && space[0][0] == '1'){
			r = 0;
			c = 0;
			space[r][c] = playerSymbol;
		}else
		if(choice == 2 && space[0][1] == '2'){
			r = 0;
			c = 1;
			space[r][c] = playerSymbol;
		}else
		if(choice == 3 && space[0][2] == '3'){
			r = 0;
			c = 2;
			space[r][c] = playerSymbol;
		}else
		if(choice == 4 && space[1][0] == '4'){
			r = 1;
			c = 0;
			space[r][c] = playerSymbol;
		}else
		if(choice == 5 && space[1][1] == '5'){
			r = 1;
			c = 1;
			space[r][c] = playerSymbol;
		}else
		if(choice == 6 && space[1][2] == '6'){
			r = 1;
			c = 2;
			space[r][c] = playerSymbol;
		}else
		if(choice == 7 && space[2][0] == '7'){
			r = 2;
			c = 0;
			space[r][c] = playerSymbol;
		}else
		if(choice == 8 && space[2][1] == '8'){
			r = 2;
			c = 1;
			space[r][c] = playerSymbol;
		}else
		if(choice == 9 && space[2][2] == '9'){
			r = 2;
			c = 2;
			space[r][c] = playerSymbol;
		} else
			r = c = -1;

		if ( r == -1 || c == -1 || space[r][c] == xPlayer || space[r][c] == oPlayer )
			cout << "Invalid move. Please enter another value.";
}


int checkWin(bool win){

	// 1 2 3 horizontal wins
	if(space[0][0] == space[0][1] && space[0][0] == space[0][2]){
		win = true;
	}else
	//4 5 6 
	if(space[1][0] == space[1][1] && space[1][0] == space[1][2]){
		win = true;	
	}else
	//7 8 9
	if(space[2][0] == space[2][1] && space[2][0] == space[2][2]){
		win = true;
	}else
	
	
	// 1 4 7 vertical wins
	if(space[0][0] == space [1][0] && space[0][0] == space[2][0]){
		win = true;
	}else
	//2 5 8
	if(space[0][1] == space[1][1] && space[0][1] == space[2][1]){
		win = true;
	}else
	//3 6 9
	if(space[0][2] == space[1][2] && space[0][2] == space[2][2]){
		win = true;
	}else
	
	//1 5 9 diagonal wins
	if(space[0][0] == space[1][1] && space[0][0] == space[2][2]){
		win = true;
	}
	//3 5 7
	if(space[0][2] == space[1][1] && space[0][2] == space[2][0]){
		win = true;
	}else
		win = false;


return win;

}

void displayWin(bool win) {


	if(win == true){
		cout << "Player  won!\n";
		
	}
}


My checkWin function doesn't seem to be operating properly. Mainly, when the requirements are met for a win, it doesn't seem to recognize the win and activate displayWin. I'm pretty sure it's a simple matter of me incorrectly passing the win variable, but no matter what I try to do with it I can't figure it out.

Any help will be greatly appreciated!
Hippogriff (727)
The problem is you are returning a bool from the checkWin function but you are not setting the value that is returned equal to anything, so it just gets lost. You would want to change it to something like win = checkWin(win); so that the value returned gets stored in win. However in this case there would be no point in passing win into the function (you would just set up a local variable inside the function and then return that.

The other way you could do it is to pass the variable by reference instead of by value. void checkWin(bool &win){ . This means that when you pass the value it actually passes the address not just a copy so it changes the original copy of the variable (and so you don't need to return anything anymore). Your choice which way to go.

Just for other side notes, makeMove is defined to return an int but it isn't returning anything right now, you may need some function definitions above main so it can see they exist. I suggest you keep your else if statements on one line or else they can be much harder for people to understand.
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