#include <iostream>
#include <string>
using namespace std;

 const int D = 3;

// Function prototypes

void clearScreen();
string getCol(string board[D][D], int c);
string getRow(string board[D][D], int r);
string getDiag(string board[D][D], int d);
bool isWinState(string state);
bool isGameOver(string board[D][D]);
void printBoard(string board[D][D]);
void updateBoard(string board[D][D], int pos, string xo);


// Main function

int main()
{

    string board[D][D] = {{"1", "2", "3"}, {"4", "5", "6"}, {"7", "8", "9"}};
    int position, turn=0;
    string xo;


    while(!isGameOver(board) && turn < 9)
    {

        clearScreen();
        printBoard (board);

        xo = "x";
        if (turn%2 == 1) xo = "o";
        cout << "Player " << turn%2+1 << "'s turn: ";
        cin >> position;
        position--;
        while(position > 8 || position < 0 || !isdigit(board[position/3][position%3][0]) || cin.fail())
        {
            cout << "Please enter in a valid position: ";
            cin >> position;
            position --;
        }

        board[position/3][position%3] = xo;

        turn ++;
    }

    clearScreen();
    printBoard (board);

    if (turn == 9)
    {
        cout << "A tie!" << endl;
    }
    else
    {
    cout << "Player " << (turn+1)%2 + 1<< " wins!" << endl;
    }
}

string getCol(string board[3][3], int c)
{
    string column  = "";
    for(int i=0; i < 3; i++) column = column + board[i][c];
    return column;
}


string getRow(string board[3][3], int r)
{
    string row = "";
    for(int i=0; i < 3; i++) row += board[r][i];
    return row;
}

string getDiag(string board[3][3], int d)
{
    string diagonal = "";
    for(int i=0; i < 3; i++) diagonal += board[i][2*d+(1-2*d)*i];
    return diagonal;
}

bool isWinState(string state)
{
    return state[0]==state[1] && state[1]==state[2]  && state[0] != ' ';
}

bool isGameOver(string board[3][3])
{
    for(int i=0; i < 3; i++) if(isWinState(getRow(board, i)) || isWinState(getCol(board,i))) return true;
    for(int i=0; i < 2; i++) if(isWinState(getDiag(board, i))) return true;
    return false;
}

void printBoard(string board[D][D])
{
    for(int i=0; i < 2; i++)
    {
        cout << " " << board[i][0] << " | " << board[i][1] << " | " << board[i][2] << endl;
        cout << "---+---+---" << endl;
    }
    cout << " " << board[2][0] << " | " << board[2][1] << " | " << board[2][2] << endl;
}

void updateBoard(string board[3][3], int pos, string xo)
{
    board[pos/3][pos%3] = xo;
}

void clearScreen()
{
    cout << string(100, '\n');
}