Creating a stand alone function that works with member functions?

[YumBerrys]

Thanks to some previous help I was able to get this program running. Now I working on taking one of my member functions and turning it into a standalone function. I choose the create_board() function. Yet, if I declare it in my header file or my main.cpp it cant access any info from the original member functions? anyone see what I'm doing wrong here? The changes that I made are in bold. Thanks!


main.cpp

#include "ticTacToe.h"
#include <iostream>
#include <limits>



void run_game()
{
    char letter_o = 'O';
    char letter_x = 'X';
    ticTacToe ttt; //creates an object "ttt" to be used with functions
    ttt.player1Piece = letter_x;
    ttt.player2Piece = letter_o;
    std::cout << "Tic Tac Toe Game\n" << std::endl;
    std::cout << "Here is a blank board: " << std::endl;
    create_board();
    while (true){
        std::cout << "\nPlayer X, it is your turn\n" << std::endl;
        ttt.update_board(letter_x);
        if (ttt.determine_winner(letter_x) == true){
            break;
        }
        std::cout << "\nPlayer O, it is your turn\n" << std::endl;
        ttt.update_board(letter_o);
        if (ttt.determine_winner(letter_o) == true){
            break;
        }
    }
}

int main() //main runs program by calling "run_game()"
{
    run_game();

}

ticTacToe.cpp

#include "ticTacToe.h"
#include <iostream>
#include <limits>


void ticTacToe::print_board(char playerPiece, int pos1 = 0, int pos2 = 0)
{
    //prints out the updated board when called upon to do so
    for(int a = 0; a < 3; a++){
        std::cout << "\n";
        for (int b = 0; b < 3; b++){
            board[pos1][pos2] = playerPiece;
            std::cout << board[a][b];
        }
    }
}


int ticTacToe::check_for_overlap(int pos1, int pos2, char playerPiece)
{
    if (board[pos1-1][pos2-1] != '-'){
        std::cout << "\nOVERLAP DETECTED!!!!!!" << std::endl;
        return true;
        }
        return false;
}


void ticTacToe::update_board(char playerPiece)
{
    //updates the board based on user input
    int x, y;
    std::cout << "Enter a position to place the " << playerPiece << " on the board" << std::endl;
    while (true){
        std::cout << "Enter row: " << std::endl;
        std::cin >> x;
        if (x < 1 || x > 3 || std::cin.fail()){
            std::cin.clear();
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n');
            std::cout << "Your number is invalid. Try again. " << std::endl;
        } else {
            break;
        }
    }

    while (true)
    {
        std::cout << "Enter col: " << std::endl;
        std::cin >> y;
        if (y < 1 || y > 3 || std::cin.fail()){
            std::cin.clear();
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n');
            std::cout << "Your number is invalid. Try again. " << std::endl;
        } else {
            break;
        }
    }

    if (check_for_overlap(x, y, player1Piece) == true){
        x--;y--;print_board(player2Piece, x, y);
        std::cout << "\nThe board has been re-set. Try again!" << std::endl;
    } else if (check_for_overlap(x, y, player2Piece) == true){
        x--;y--;print_board(player1Piece, x, y);
        std::cout << "\nThe board has been re-set. Try again." << std::endl;
    } else {
        x--;y--;print_board(playerPiece, x, y);
    }
}


int ticTacToe::determine_winner(char playerPiece)
{
    /*slices the board and checks if playerPiece occupies that slot.
    If the player makes a line, print that playerPiece has won
    and exit the game.*/
    if (board[0][0] == playerPiece && board[0][1] == playerPiece && board[0][2] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[1][0] == playerPiece && board[1][1] == playerPiece && board[1][2] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[2][0] == playerPiece && board[2][1] == playerPiece && board[2][2] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[0][0] == playerPiece && board[1][0] == playerPiece && board[2][0] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[0][1] == playerPiece && board[1][1] == playerPiece && board[2][1] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[0][2] == playerPiece && board[1][2] == playerPiece && board[2][2] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[0][0] == playerPiece && board[1][1] == playerPiece && board[2][2] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    }
    else if(board[0][2] == playerPiece && board[1][1] == playerPiece && board[2][0] == playerPiece){
        std::cout << "\nPlayer " << playerPiece << " wins!" << std::endl;
        return true;
    } else {
        return false;
    }
}

ticTacToe.h

#ifndef TICTACTOE_H_INCLUDED
#define TICTACTOE_H_INCLUDED

void create_board();

void create_board()
{
    //creates a blank board
    for(int a = 0; a < 3; a++){
       std::cout << "\n";
        for (int b = 0; b < 3; b++){
            board[a][b] = '-';
          std::cout << board[a][b];
        }
    }
}




class ticTacToe
{
    public: //Allow us to use the functions anywhere
    char player1Piece; //variable used in multiple functions
    char player2Piece; //variable used in multiple functions


    void print_board(char playerPiece, int pos1, int pos2);
    int check_for_overlap(int pos1, int pos2, char playerPiece);
    void update_board(char playerPiece);
    int determine_winner(char playerPiece);

    char board[3][3]; //Creates an 2d array for the board
};





#endif // TICTACTOE_H_INCLUDED

[pheininger]

Now I working on taking one of my member functions and turning it into a standalone function.

Why?

Have you considered changing it into the constructor for ticTacToe?

If you still want to make it a stand-alone, you probably need to pass the board to the function. For example: if some code looked like:

#include "ticTacToe.h"
...
int main(void)
{
    ticTacToe ttt;
    ticTacToe vvv;
    ticTacToe zzz;

    create_board();  /* Which board should this create? */

}

One possible declaration void create_board(char board[3][3]);
You may then be able to call it with create_board(ttt.board);[Untested idea.]

You have put the declaration for create_board in ticTacToe.h. Why not put it into its own header file for example board.h?

You also have put the definition into ticTacToe.h. Why did you put there? I would suggest that you put the definition into one of board.cpp, main.cpp, or ticTacToe.cpp.

[Duthomhas]

I'm confused as to why you are trying to do this.
First, you want to access an unknown object's internal fields from a global function (don't do that).
Second, you are separating an object's creation/initialization from the object itself (don't do that).

tl;dr leave it as a member function.

Hope this helps.