CC150 17.2

17_2.cpp

/* CC150 17.2 */
// determine if someone has won a game of tic-tac-toe
// (expand to a full game!)

#include <iostream>

using namespace std;

// assume only one row satisfying the condition exists since the games ends once a player succeeded
// in placing three respective marks in a horizontal, vertical or diagonal row.
bool isEmpty(char grid) { return grid != 'x' && grid != 'o'; }
bool hasWon(char **board, int n)
{
	if (n < 1)
		return false;
	int i = 0, j = 0;
	// check rows
	for (i = 0; i != n; ++i) {
		if (isEmpty(board[i][0]))
			continue;
		for (j = 0; j != n; ++j) {
			if (board[i][j] != board[i][0])
				break;
		}
		if (j == n) {
			cout << "Row #" << i << " won by " << board[i][0] << endl;
			return true;
		}
	}
	// check columns
	for (i = 0; i != n; ++i) {
		if (isEmpty(board[0][i]))
			continue;
		for (j = 0; j != n; ++j) {
			if (board[j][i] != board[0][i])
				break;
		}
		if (j == n) {
			cout << "Column #" << i << " won by " << board[0][i] << endl;
			return true;
		}
	}
	// check diagonal
	for (i = 0; i != n; ++i) {
		if (isEmpty(board[0][0]) || board[i][i] != board[0][0])
			break;
	}
	if (i == n) {
		cout << "Diagonal won by " << board[0][0] << endl;
		return true;
	}
	// check reverse diagonal
	for (i = 0; i != n; ++i) {
		if (isEmpty(board[0][n - 1]) || board[i][n - 1 - i] != board[0][n - 1])
			break;
	}
	if (i == n) {
		cout << "Reverse diagonal won by " << board[0][n - 1] << endl;
		return true;
	}
	cout << "No player won...keep going..." << endl;
	return false;
}

int main()
{
	int n;
	cout << "Board size: ";
	cin >> n;
	char **board = new char*[n];
	for (int i = 0; i != n; ++i) {
		board[i] = new char[n];
		for (int j = 0; j != n; ++j)
			cin >> board[i][j]; // represent with -/x/o
	}
	bool result = hasWon(board, n);
	return 0;
}