Ok, I'm learning C++, and here's the code for a little tic-tac-toe game I've written. At the end, I'd like to be able to provide the user with a choice of yes or no to keep playing, but I have problems telling my app to quit right then and there. Here's the code; please someone show me how to do this!
Code:
#include <iostream.h>
#include <stdlib.h>
#include <time.h>

char board[3][3];
int hAxis;
int vAxis;
int lineCheck;
char uRes;
char cWin;
int pTurn = 0;
long xWins = 0;
long oWins = 0;
long cWins = 0;

void endGame(char);
char isWinner();
void mainGame();


void main()
{
srand(time(NULL));
board[0][0] = ' '; 
board[0][1] = ' ';
board[0][2] = ' ';
board[1][0] = ' ';
board[1][1] = ' ';
board[1][2] = ' ';
board[2][0] = ' ';
board[2][1] = ' ';
board[2][2] = ' ';
cout << "Welcome to Tic-Tac-Toe!\nYou are player 'X'" << endl;
mainGame();
cout << "\n\nThanks for playing!";
} 

void mainGame()
{
	cout << endl << "MainGame" << endl;
	int hComp;
	int vComp;

		do{
			do{
				cout << "\n 1 2 3\n" <<
				"1" << board[0][0] << "|" << board[0][1] << "|" << board[0][2] <<
				"\n -+-+-\n" << 
				"2" << board[1][0] << "|" << board[1][1] << "|" << board[1][2] <<
				"\n -+-+-\n" << 
				"3" << board[2][0] << "|" << board[2][1] << "|" << board[2][2] << endl << endl;
				
				do{
					cout << "Enter Horizontal: ";
					cin >> hAxis;
				}while (hAxis > 3 && hAxis < 1);
				do{
					cout << "Enter Vertical: ";
					cin >> vAxis;
				}while (vAxis > 3 && vAxis < 1);
				
				if (board[vAxis - 1][hAxis - 1] != ' '){cout << "\nThat space is already occupied by '" << board[vAxis - 1][hAxis - 1] << "'!" << endl;};
			}while(board[vAxis - 1][hAxis - 1] != ' ');
			
			board[vAxis - 1][hAxis - 1] = 'X';

			cWin = isWinner();
			if(cWin != ' ') endGame(cWin);
			else{ 

				if (pTurn < 4){
				do{
					hComp = rand() % 3;
					vComp = rand() % 3;
				}while (board[vComp][hComp] != ' ');
				board[vComp][hComp] = 'O';
				};
			
				cWin = isWinner();
				if(cWin != ' ') endGame(cWin);
				else pTurn = pTurn + 1;
			}
		}while(pTurn < 5);
	endGame(isWinner());
}

char isWinner()
{
	lineCheck = (int)board[0][0] + (int)board[0][1] + (int)board[0][2];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	lineCheck = (int)board[1][0] + (int)board[1][1] + (int)board[1][2];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	lineCheck = (int)board[2][0] + (int)board[2][1] + (int)board[2][2];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	
	lineCheck = (int)board[0][0] + (int)board[1][0] + (int)board[2][0];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	lineCheck = (int)board[0][1] + (int)board[1][1] + (int)board[2][1];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	lineCheck = (int)board[0][2] + (int)board[1][2] + (int)board[2][2];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);

	lineCheck = (int)board[0][0] + (int)board[1][1] + (int)board[2][2];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);

	lineCheck = (int)board[0][2] + (int)board[1][1] + (int)board[2][0];
	if(lineCheck == 264 || lineCheck == 237) return (char)(lineCheck / 3);
	return ' ';
}

void endGame(char winner)
{
	cout << "\n 1 2 3\n" <<
	"1" << board[0][0] << "|" << board[0][1] << "|" << board[0][2] <<
	"\n -+-+-\n" << 
	"2" << board[1][0] << "|" << board[1][1] << "|" << board[1][2] <<
	"\n -+-+-\n" << 
	"3" << board[2][0] << "|" << board[2][1] << "|" << board[2][2] << "\n\n";

	switch(cWin)
	{case 'X': cout << "'X' wins the game!"; xWins = xWins + 1; break;
	case 'O': cout << "'O' wins the game!"; oWins = oWins + 1; break;
	case ' ': cout << "It's a cat's game!"; cWins = cWins + 1; break;}
	
	cout << "\n\nScoreboard:\n-----------\nX Wins: " << xWins << "\nO Wins: " << oWins << "\nCat's Games: " << cWins << 
		"\n\nWould you like to play again? (Y/N): ";

	board[0][0] = ' '; 
	board[0][1] = ' ';
	board[0][2] = ' ';
	board[1][0] = ' ';
	board[1][1] = ' ';
	board[1][2] = ' ';
	board[2][0] = ' ';
	board[2][1] = ' ';
	board[2][2] = ' ';

	cin >> winner;
	if (uRes != 'Y' || uRes != 'y') //now what?
}
Also note that a lot of this code has been written pretty beginner-like, so please feel free to show me other ways of doing this stuff. Please mark code you create or edit by adding //* or something so I will know! Thanks!