This C++ program implements a tic-tac-toe game. It includes functions to display the game board, prompt player moves, check for a win or tie, and reset the board. The main function calls other functions to run the game flow, which prompts players to take turns making moves until there is a win or tie. It then asks if the players want to play again before ending. Key elements include an array to track the game board positions, boolean flags to track players, and check functions to validate moves and detect game status.

1. //http://www.cplusplus.com/reference/cctype/
//http://en.cppreference.com/w/cpp/string/basic_string/to_string
//#include <climits>// limits of named constants, see page 1284
//#include <cmath> //math library
//#include <cctype> // library for strings and other useful validations
#include <iomanip> // library for manipulating output
//#include <fstream> // library to direct output to files and get input from
files
//#include <cstdlib> // library for the rand and srand functions
//#include <ctime> // library to work with time
//#include <string> //string library
//#include <cstring> //to be able to use strlen
//#define NDEBUG
//#include <assert.h>
//#include <array>
//#include <typeinfo>// ----typeid(varName).name()
#include <iostream>
using namespace std;
//Declare Functions
void displayMessage();
void refresh();
void move(bool who);
int checkWin();
int checkUse(int n);
int checkTie();
int checkTie2();
void playAgain();
void reset();
//Declare public Vars
char pos[9] = { '0', '1', '2', '3', '4', '5', '6', '7', '8' }; //Grid Positions
char res[9] = { '0', '1', '2', '3', '4', '5', '6', '7', '8' }; //For Reseting
int mov;//Grid Choice
bool player = true;//True = 'X' False = 'O'
//Main Function
void main()
{
refresh();
move(player);
}
//Display Title at start
void displayMessage()
{
cout << "+----------------------------+" << endl;
cout << "|Tic Tac Toe |" << endl;
cout << "| Your Name |" << endl;
cout << "|____________________________|" << endl;
cout << endl;
}
//Display Grid on screen
void refresh()
{
system("cls");
displayMessage();
cout << endl;
cout << "" << pos[0] << "|" << pos[1] << "|" << pos[2] << endl;
cout << "-----" << endl;
cout << "" << pos[3] << "|" << pos[4] << "|" << pos[5] << endl;
cout << "-----" << endl;
cout << "" << pos[6] << "|" << pos[7] << "|" << pos[8] << endl;
}
//Prompt users move/Test for win,tie,pos in-use

2. void move(bool who)
{
if(who == true)
{
cout << endl;
cout << "Make your move Player 1: ";
while(1)
{
cin >> mov; //Enter Grid Position
if(checkUse(mov))
{
cout << endl;
cout << "Sorry, that position is in use" << endl;
cout << " Try again: " << endl;
}
else
break;
}
pos[mov] = 'X'; //Set selected position to 'X'
refresh();
if(checkTie())
{
cout << endl;
cout << " Tie Game!" << endl;
playAgain();
}
//Check for win
if(checkWin())
{
cout << endl;
cout << "Player 1 Wins" << endl;
playAgain();
}
else
{
player = false;//Switch Player
move(player); //Player 2's turn
}
}
else
{
cout << endl;
cout << "Make your move Player 2: ";
while(1)
{
cin >> mov; //Ask for position
if(checkUse(mov))
{
cout << endl;
cout << "Sorry that position is in use" << endl;
cout << " Try again: " << endl;
}
else
break;
}

3. pos[mov] = 'O';
refresh();
if(checkTie())
{
cout << endl;
cout << " Tie Game!" << endl;
playAgain();
}
if(checkWin())
{
cout << endl;
cout << "Player 2 Wins" << endl;
playAgain();
}
else
{
player = true; //Switch Player
move(player);//Player 1's turn
}
}
}
//Check for used position
int checkUse(int n)
{
if(pos[n] == 'X' || pos[n] == 'O')
return true;
else
return false;
}
//Check for Win
int checkWin()
{
if(pos[0] == pos[1] && pos[0] == pos[2])
return true;
if(pos[0] == pos[3] && pos[0] == pos[6])
return true;
if(pos[0] == pos[4] && pos[0] == pos[8])
return true;
if(pos[1] == pos[4] && pos[1] == pos[7])
return true;
if(pos[2] == pos[4] && pos[2] == pos[6])
return true;
if(pos[2] == pos[5] && pos[2] == pos[8])
return true;
if(pos[3] == pos[4] && pos[3] == pos[5])
return true;
if(pos[6] == pos[7] && pos[6] == pos[8])
return true;
else
return false;
}
//Check for Tie
int checkTie()
{
if(pos[0] != '0' && pos[1] != '1' && pos[2] != '2' && pos[3] != '3' &&
pos[4] != '4'
&& pos[5] != '5' && pos[6] != '6' && pos[7] != '7' && pos[8] != '8')
return true;
else

4. return false;
}
//Play Again Prompt
void playAgain()
{
char choice;
cout << endl;
cout << "Do you wish to play again: Y? N?";
//Loop question in case of error
while(1)
{
cin >> choice;
if(choice == 'y'|| choice == 'y')
{
player = true;//Restart with Player 1 starting
reset(); //Reset position array
refresh();//Restart Grid
move(player);//Player start
}
else if(choice == 'n' || choice == 'N')
{
cout << endl;
cout << "Thanks for playing!" << endl;
break; //Quit Game
}
else //Reloop
{
cout << endl;
cout << " Please enter either 'n' or 'y'";
}
}
}
//Reseting Grid After Restart
void reset()
{
for(int i = 0; i <= 9; i++)
pos[i] = res[i];
}