Question

Greetings,

Since my last question about C++, I actually learned quite an amount. I am now comfortable with classes, just not so comfortable with pointers and references yet.

Please note, I am not asking you nesceserally to solve my problem, I’m asking why I’m not getting the wished result.

here are some code snippets that that should help me explain the problem:
Im making a console based tic-tac-toe game(recently started learning C++, this imo is a good way for it)

main.cpp:

//Here I initalise 1 variable and an array
int move;
char board[9] = {' ',' ',' ',' ',' ',' ',' ',' ',' '};

First question: Is there a better way to define empty spaces in a char array?
The reason i’m doing it like this is, I want my tictactoe board to contain an empty space when an X or O has not been set yet.

main.cpp:

if(referee.validateMove(board, move))
{
   board[move] = player2.getToken();
   displayBoard(board);
}

What happens here is easily understood but i’ll explain anyway;

A call to the validateMove method from the object referee is made, and passed 2 paramaters, the move that the player has selected (in between 0-8). and the tictactoe board.

Referee.cpp

bool Referee::validateMove(const char (&board)[9], int& move)
{
    if(board[move] != 'X' || 'O')
    {
        return true;
    } 
    else 
    {
        return false;
    }
}

Here is where the main trouble is, and my last question arises.
As seen before, I passed an array of chars with a size of 9.

The reference to the move variable works well(should i use a reference or pointer?) and it contains the wished result.

At this point, say player 1 just made its move and placed a token in position 2
I now want to place my token as PLAYER 2 on position 2

When I debug with visual studio, I get the following:

0x0024faa8 "  O      ÌÌÌÌÌÌÌÌÌÌÌ"

This is when i hold my mouse on the board parameter.
So the board does know, it is occupied.

Why however does the validateMove method always return true, and is board[move] never equal to O or X?

Thank you for taking the time to read my problem. If you have a question, or I explained something in a stupid matter, you see invalid naming conventions, please notify me. I am a student, and I want to pick up as much as possible.

This problem is resolved. Thanks for those who have answered. Highly appreciate it.

Answer 1

Your condition boils down to this:

if((board[move] != 'X') || ('O'))

'O' will always evaluate to true in this case, so you always pass the condition. What you want is this:

if((board[move] != 'X') && (board[move] != 'O'))

To verify, this code runs fine for me:

#include <iostream>

bool validateMove(const char (&board)[9], int move)
{
    if((board[move] != 'X') && (board[move] != 'O'))
    {
        std::cout << "True" << std::endl;
        return true;
    } 
    else 
    {
        std::cout << "False" << std::endl;
        return false;
    }
}


int main()
{
    char board[9] = {' ',' ','O',' ','X',' ',' ',' ',' ',};

    validateMove(board, 0);
    validateMove(board, 2);
    validateMove(board, 4);
}

The output is:

True
False
False