Question

Write a class (and a client class to test it) that encapsulates a tic-tac-toe board. A tic-tac-toe board looks like a table of three rows and three columns partially or completely filled with the characters X and O. At any point, a cell of that table could be empty or could contain an X or an O. You should have one instance variable, a two-dimensional array of values representing the tic-tac-toe board.

This game should involve one human player vs. the computer (aka, it should be a one player game). At the start of each game, randomly select if the computer will play X or O and who (i.e. human or computer) will make the first move.

Your default constructor should instantiate the array so that it represents an empty board.

You should include the following methods:

a method that generates a valid play by the computer and displays the board after each play.

a method that requests a valid play from the human and displays the board after each play.

a method to display the tic-tac-toe board.

a method checking if a player has won based on the contents of the board; this method takes no parameter. It returns X if the "X player" has won, O if the "O player" has won, T if the game was a tie. A player wins if he or she has placed an X (or an O) in all cells in a row, all cells in a column, or all cells in one of the diagonals.

NOTE: Be sure to display the board after each move. You must provide clear prompts for the human player to select a space on the tic-tac-toe board.

Input Validation: Verify that all moves by the human player are to a valid space on the tic-tac-toe board. An incorrect choice should not halt or terminate the game. Also, no human vs. human mode should be included in the program. Just Human vs. the Computer is what the game should only involve.

Answer 1

// tictactoe.cpp
#include <vector>
#include <iostream>

using namespace std;

const bool CLEAR_SCREEN = true;

void clearScreen()
{
cout << endl;

if (CLEAR_SCREEN)
{
cout << "\033c";
}

cout << endl;
}

void drawBoard(const vector <char> &board)
{
clearScreen();
for (int i = 0; i < 9; i += 3)
{
cout << " " << board.at(i) << " | " << board.at(i + 1) << " | "
<< board.at(i + 2) << " " << endl;
if (i < 6)
cout << "-----|-----|-----" << endl;
}
cout << endl;
}

void initVector(vector <char> &v)
{
if (v.size() <= 26)
{
for (int idx = 0; idx < v.size(); idx++)
{
v.at(idx) = 'a' + idx;
}
}
  
return;
}

int convertPosition(char position)
{

vector <char> newVector(9);
  
  
initVector(newVector);

for (int idx = 0; idx < newVector.size(); idx++)
{
if (position == newVector.at(idx))
return idx;
}
  
return 10;
}

bool validPlacement(const vector <char> &board, int position)
{
  
if (position < board.size())
{
if ((board.at(position) != 'o' && board.at(position) != 'x'))
return true;
}
else
return false;
}

int getPlay(const vector <char> &board)
{
int idx;
char userPosition;

do
{
cout << "Please choose a position: ";
cin >> userPosition;
cout << endl;
  
idx = convertPosition (userPosition);
} while ((!validPlacement(board, idx)));
return idx;
}

bool gameWon(const vector <char> &board)
{
for (int idx = 0; idx < 3; idx++)
{
if (board.at(3*idx) == board.at(3*idx+1) && board.at(3*idx+1) == board.at(3*idx+2))
return true;
else if (board.at(idx) == board.at(idx+3) && board.at(idx+3) == board.at(idx+6))
return true;
}
  
if (board.at(2) == board.at(4) && board.at(4) == board.at(6))
return true;
else if (board.at(0) == board.at(4) && board.at(4) == board.at(8))
return true;
  
  
return false;
}

bool boardFull(const vector <char> &board)
{
int idxJ = 0;
for (int idx = 0; idx < board.size(); idx++)
{
if (board.at(idx) == 'o' || board.at(idx) == 'x')
idxJ++;
}
  
if(idxJ == 9)
return true;
else
return false;
}

const int PLAYER1 = 0;
const int PLAYER2 = 1;

int main()
{
  
vector <char> board(9);
int curPlay;
int turn = PLAYER1;

initVector(board);

drawBoard(board);

while (!boardFull(board) && !gameWon(board))
{
curPlay = getPlay(board);
  
board.at(curPlay) = (turn == PLAYER1) ? 'x' : 'o';
  
if (!boardFull(board) && !gameWon(board))
{
if (turn == PLAYER1)
turn = PLAYER2;
else if (turn == PLAYER2)
turn = PLAYER1;
}
  
drawBoard(board);
}

if (turn == PLAYER1 && gameWon(board))
cout << "Player (x's) wins!" << endl << endl;
else if (turn == PLAYER2 && gameWon(board))
cout << "Computer (o's) wins!" << endl << endl;
else
cout << "No one wins" << endl << endl;

return 0;
}