Main

main.cpp

#include "TicTacToe.h"
#include<iostream>
using namespace std;
int main()
{
int choice;
int count;
int winner = 0;
char computer = 'O';
char user= 'X';
TicTacToe gameStart;
cout<< "The user is first" << endl;
cout << "User : X" << endl;
cout << "Computer : O" <<endl;

// Counter for game. If there are 4 loops(total of 8 slots of 9 on the board filled from both user and computer)
// without a winner then the game will be a draw.
for (count = 0; count < 4 && winner == 0; count ++)
{
    gameStart.printBoard();
    gameStart.playerTurn(user);
    gameStart.computerTurn(computer);

    winner = gameStart.winCheck();
}
if (winner == 0)
{
    cout << "Game Draw" << endl;
}
else if (winner == computer)
{
    cout << "Computer wins" << endl;
}
else
{
    cout << "User won" << endl;
}
return 0;
}

TicTacToe.cpp

#include "TicTacToe.h"
#include<iostream>
#include<stdlib.h>
using namespace std;
TicTacToe::TicTacToe()
{
int n = 1;
int i = 0;
int j = 0;

for (i = 0; i < 3; i++)
{
    for (j = 0; j < 3; j++)
    {
        game[i][j] = '0' + n;
        n++;

    }
}
}

void TicTacToe::printBoard()
{
for(int i = 0; i < 3; i++)
{
    for (int j = 0; j < 3; j++)
    if (j != 2)
    cout << game[i][j] << "|";
    else
    cout << game[i][j];
    cout << endl;
}
}
void TicTacToe::computerTurn(char ch)
{
bool validPosition= false;
do{
    int number = rand()%9+1;
    char num = '0' + number;
    int i = 0;
    int j = 0;
    for (i = 0; i < 3; i++)
    {
        if (validPosition == true)
            break;
        for ( j = 0; j < 3; j++)
        {
        if (game[i][j] == num)
        {

            game[i][j] = ch;
            validPosition = true;
            break;
        }
        else
        {
            validPosition = false;
        }
        }
    }
}while((!validPosition));
}
void TicTacToe::playerTurn(char ch)
{
bool validPosition= false;
do{
    cout << "Enter a position: ";
    int pos;
    cin >> pos;
    char num = '0'+ pos;
    int i = 0;
    int j = 0;
    for (i = 0; i < 3; i++)
    {
    if (validPosition == true)
        break;
    for ( j = 0; j < 3; j++)
    {
        if (game[i][j] == num)
        {
            cout << endl;
            game[i][j] = ch;
            validPosition = true;
            break;
        }
        else
        {
            validPosition = false;
        }
    }
    }
}while((!validPosition));
}

char TicTacToe::winCheck()
{
int i, j;
for (i = 0; i < 3; i++)
{
    for (j = 0; j < 3; j++)
        if (game[i][j] != 'X')
        break;
        if (j == 3)
        return 'X';
    for (j = 0; j < 3; j++)
        if (game[i][j] != 'O')
        break;
        if (j == 3)
        return 'O';
    for (j = 0; j < 3; j++)
        if (game[j][i] != 'X')
        break;
        if (j == 3)
        return 'X';
    for (j = 0; j < 3; j++)
        if (game[j][i] != 'O')
        break;
        if (j == 3)
        return 'O';
}
if (game[0][0] == game[1][1] == game[2][2] =='X')
    return 'X';
if (game[0][2] == game[1][1] == game[2][0]=='X')
    return 'X';

return 0;
}

TicTacToe.h

#ifndef TICTACTOE_H
#define TICTACTOE_H
#include<iostream>
class TicTacToe
{
private: char game[3][3];
public:
TicTacToe();
void printBoard();
void computerTurn(char ch);
void playerTurn (char ch);
char winCheck();
};
#endif // TICTACTOE_H