[C++]

Create a program using a two dimension array and functions that lets two players play the tic-tac-toe game. The program is to read a number from 1 to 9 from the keyboard alternating between the X and the O. Ask which square the X player wants, and then ask which square the O player wants. Continue until the game is won by either player, or all the squares have been filled. (Called a Cat's Game or a Tie Game)

A function must be used to display the tic-tac-toe game board, and a function must be used that determines if the game has been won.

#include // needed for cin and cout #include // needed by srand() and srand() #include // needed for the time() function using namespace std;

// function prototypes void DisplayTicTacToe(char board[3][3]); char CheckForWinningGame(char board[3][3]);

int main(int argc, char* argv[]) { char board[3][3] = { // index for positions in the array {'1', '2', '3'}, // [0][0] [0][1] [0][2] {'4', '5', '6'}, // [1][0] [1][1] [1][2] {'7', '8', '9'} // [2][0] [2][1] [2][2] };

int squareCounter = 0; // count how many squares are used char gameWinner = '-'; // winner of the game ('X' or 'O') char inputCharacter; // input from the user (should be '1' to '9') int choice; // input converted to integer 0 to 8 (start from 0) char player; // current player, set to either an 'X' or an 'O'

// select the starting player srand( (unsigned int)time(NULL)); // seed the random number generator if ( rand() % 2 == 1) player = 'X'; else player = 'O';

// starting instructions cout << "Enter a 1 though 9 to select a square." << endl;

// Ask for a 1-9 until all squares are filled or the game has been won while (squareCounter < 9 && gameWinner != 'X' && gameWinner != 'O') { DisplayTicTacToe(board); cout << "Player " << player << ", enter a number (1-9): "; cin >> inputCharacter;

// Arrays start counting from index 0 // convert inputCharacter from ASCII ('1' to '9') to integer (0 to 8) // to select the row and column index for the 3x3 array choice = inputCharacter - '1'; // now the inputs are 0,1,2,3,4,5,6,7,8 int row = choice / 3; // row will be 0 (for 0,1,2), 1 (for 3,4,5), 2 for (6,7,8) int col = choice % 3; // col will be 0 (for 0,3,6), 1 (for 1,4,7), 2 for (2,5,8)

if (choice < 0 || choice > 8) // see if the input is below 1 or greater than 0 cout << "Illegal value, try again" << endl; else if (board[row][col]=='X' || board[row][col]=='O') cout << "This space has already been used, try again" << endl; else { board[row][col] = player; // put in an 'X' or an 'O' squareCounter++; // count the number of squares completed // select the next player if (player=='X') player = 'O'; // switch from 'X' to 'O' for next move else player = 'X'; // switch from 'O' to 'X' for next move } gameWinner = CheckForWinningGame(board); // returns 'X' or 'O' if the game is won } if (squareCounter == 9) { DisplayTicTacToe(board); cout << endl << "Tie Game" << endl << endl; } else if (gameWinner =='X' || gameWinner == 'O') { DisplayTicTacToe(board); cout << endl << "Player " << gameWinner << " wins the game" << endl << endl; } return 0; }

// ------ Display the Tic Tac Toe board void DisplayTicTacToe(char board[3][3]) { cout << endl; for (int row=0; row<3; row++) // display three rows { for (int col=0; col<3; col++) // display three columns each row cout << board[row][col] << ' '; cout << endl; // end of row } cout << "--------------------------------" << endl << endl;; }

// ------ Check all eight possible combinations for a win. // returns the player ('X' or 'O') if the game has been won // returns '-' if there is currently no winner char CheckForWinningGame(char board[3][3]) { char player;

// check going across the top row to see if all squares are the same player = board[0][0]; if (board[0][1] == player && board[0][2] == player) return player;

// check going across the middle row to see if all squares are the same

// check going across the bottom row to see if all squares are the same

// check going down the first column to see if all squares are the same

// check going down the second column to see if all squares are the same

// check going down the third column to see if all squares are the same

// check going across the left diagonal \ to see if all squares are the same

// check going across the right diagonal / to see if all squares are the same

return '-'; // if there is no winner }