Tic tac toe game help

Hi everyone,

I have a few issues with my new program, which is making the tic tac toe game from Jumping Into C++. There is another thread about this (we are obviously using the same book, at the same time!). This is causing slight issues in me not wanting to view the other thread in case it gives away the answers. So, I am working at this and my problems follow the code:

Code:

---

//  Tic tac toe
//  Created by Sam on 21/04/2013.

#include <iostream>

//Top right (TR), Centre left (CL), Bottom Middle (BM) etc...
void printGameBoard(char TL, char TM, char TR, char CL, char CM, char CR, char BL, char BM, char BR);
void facilitateMove(int squareChoice);

//initialize values for starting board
char TL('1');
char TM('2');
char TR('3');
char CL('4');
char CM('5');
char CR('6');
char BL('7');
char BM('8');
char BR('9');

//variable to hold the 'X' for player 1, and 'O' for player 2
char playerMarker;

int main()
{
    enum SquareStates {SS_O, SS_X, SS_HAS_NUMBER}; //3 states - has a 'O', has a 'X', has a number '1', '2' etc...
    SquareStates currentValue; //current value of the square on the board, SS_O, SS_X or SS_HAS_NUMBER
    //the board squares already have a value 1, 2, 3, 4... so how to use SS_HAS_NUMBER?
   
    //variable to switch whos turn it is (starts with player 1 == true)
    int playerTurn = 1;
   
    //after game is finished, a choice for another go
    bool anotherGo = 1;
   
    //saves the number a user has inputted to compare with enums (??) for allowed/illegal move
    char squareChoice;
   
    do
    {
        //set markers for each player
        if (playerTurn == 1)
        {
            playerMarker = 'X';
        }
        else
        {
            playerMarker = 'O';
        }
       
        //prints game board with updated variables depending on player move
        printGameBoard(TL, TM, TR, CL, CM, CR, BL, BM, BR);
       
        std::cout << "Player " << playerTurn << ", your go: ";
        std::cin >> squareChoice;
       
        //CHECK MOVE IS LEGAL
        /* I planned to use like this, presuming player 1 is using an 'X':
       
        if(player1 == 1 && currentValue == SS_X)
        {
        illegal move
        }
       
        if(player2 == 1 && currentValue == SS_O)
        {
        illegal move
        }
        */
       
        //facilitate move
        facilitateMove(squareChoice);
       
        //switches between player 1 and player 2 turn after each move
        if (playerTurn == 1)
        {
            playerTurn = 2;
        }
        else
        {
            playerTurn = 1;
        }
       
    } while (anotherGo == 1);
}

void printGameBoard(char TL, char TM, char TR, char CL, char CM, char CR, char BL, char BM, char BR)
{
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << TL << "|" << TM << "|" << TR << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << CL << "|" << CM << "|" << CR << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << BL << "|" << BM << "|" << BR << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
}

void facilitateMove(int squareChoice)
{
    switch(squareChoice)
    {
        case '1':
            TL = playerMarker;
            break;
        case '2':
            TM = playerMarker;
            break;
        case '3':
            TR = playerMarker;
            break;
        case '4':
            CL = playerMarker;
            break;
        case '5':
            CM = playerMarker;
            break;
        case '6':
            CR = playerMarker;
            break;
        case '7':
            BL = playerMarker;
            break;
        case '8':
            BM = playerMarker;
            break;
        case '9':
            BR = playerMarker;
            break;
    }
}

---

What works:

1) Switching players
2) Using correct marker for each player (X, O etc..)

Problems:

1) I am using global variables, is there a way around this other than dumping it all in main, or is it suitable for this program?

2) How do I get my enums involved? It hasn't yet clicked with me on how to actually use them. There are 3 states to each square on the board, a number, a 'X' or a 'O'.

I have a few ideas which I have commented in but the lightbulb is most certainly out right now! Once I understand how to use the enums, I think it will be a lot easier getting the logic for:

a) when a move is illegal
c) when someone has won

Just a bit stuck. Any help is very appreciated, thanks.

Quote:

---

1) I am using global variables, is there a way around this other than dumping it all in main, or is it suitable for this program?

---

you can use global variables if you want but if you do there is no need to pass them as arguments to your functions (that's what makes them global), so if you try:

Code:

---

#include <iostream>
char test[]="xpto";
void printtest(){
  std::cout<<test;
}
main(){
  printtest();
}

---

you will notice that it works.

you could instead of declaring 9 separate variables just declare an array "board[3][3]", it would probably even facilitate the code when you implement a "check win condition" function.

edit: and you seem to know this since you used it for your second function, however for the 1st know that the local scope superseeds the global variables, I mean, if you name a global variable "TL" and then make a function void f1(char TL) inside that function TL means "the argument that was passed to me" so if you then call that function with a different argument, f1(TM) for example, it will do its operations with TM.
Worst of all, this is not a syntax error, so it will compile correctly, and it doesn't "look wrong" so it would be a great way for you to spend hours looking for a bug in a larger project simply because "TL is not TL inside that function"

Ok, I converted the many variables at the top into an array and updated the appropriate conditions:

Code:

---

//  Tic tac toe
//  Created by Sam on 21/04/2013.

#include <iostream>

char gameBoard [3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}};

void printGameBoard();

//variable to hold the 'X' for player 1, and 'O' for player 2
char playerMarker;

int main()
{
   
    //variable to switch whos turn it is (starts with player 1 == true)
    int playerTurn = 1;
   
    //after game is finished, a choice for another go
    bool bAnotherGo = 1;
   
    do
    {
        //set markers for each player
        if (playerTurn == 1)
        {
            playerMarker = 'X';
        }
        else
        {
            playerMarker = 'O';
        }
       
        //prints game board with updated variables depending on player move
        printGameBoard();
       
        std::cout << "Player " << playerTurn << ", your go: ";
        //saves the number a user has inputted to compare with enums (??) for allowed/illegal move
        char squareChoice;
        std::cin >> squareChoice;
        bool bIsValid;
       
       
        do {
           
            bIsValid = true;
           
           
            // Check for a valid move
           
            if (squareChoice == '1' && gameBoard[0][0] == '1')
            {
               
                gameBoard[0][0] = playerMarker;
               
            }
            else if (squareChoice == '2' && gameBoard[0][1] == '2')
            {
               
                gameBoard[0][1] = playerMarker;
               
            }
            else if (squareChoice == '3' && gameBoard[0][2] == '3')
            {
               
                gameBoard[0][2] = playerMarker;
               
            }
            else if (squareChoice == '4' && gameBoard[1][0] == '4')
            {
               
                gameBoard[1][0] = playerMarker;
               
            }
            else if (squareChoice == '5' && gameBoard[1][1] == '5')
            {
               
                gameBoard[1][1] = playerMarker;
               
            }
            else if (squareChoice == '6' && gameBoard[1][2] == '6')
            {
               
                gameBoard[1][2] = playerMarker;
               
            }
            else if (squareChoice == '7' && gameBoard[2][0] == '7')
            {
               
                gameBoard[2][0] = playerMarker;
               
            }
            else if (squareChoice == '8' && gameBoard[2][1] == '8')
            {
               
                gameBoard[2][1] = playerMarker;
               
            }
            else if (squareChoice == '9' && gameBoard[2][2] == '9')
            {
               
                gameBoard[2][2] = playerMarker;
               
            }
            else
            {
                std::cout << "Invalid Move. Try again: ";
                std::cin >> squareChoice;
                bIsValid = false;
               
            }
           
        } while (!bIsValid);
       
        //switches between player 1 and player 2 turn after each move
        if (playerTurn == 1)
        {
            playerTurn = 2;
        }
        else
        {
            playerTurn = 1;
        }
       
    } while (bAnotherGo == 1);
}

void printGameBoard()
{
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << gameBoard[0][0] << "|" << gameBoard[0][1] << "|" << gameBoard[0][2] << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << gameBoard[1][0] << "|" << gameBoard[1][1] << "|" << gameBoard[1][2] << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
    std::cout << "|" << gameBoard[2][0] << "|" << gameBoard[2][1] << "|" << gameBoard[2][2] << "|" << std::endl;
    std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
}

---

'void printGameBoard' could be done in a loop by the looks of the pattern to save typing gameBoard[n][n] so many times.

As it stands then, I find it pretty hard to read!

Quote:

---

Originally Posted by killme

you can use global variables if you want but if you do there is no need to pass them as arguments to your functions (that's what makes them global), so if you try:

Code:

---

#include <iostream>
char test[]="xpto";
void printtest(){
  std::cout<<test;
}
main(){
  printtest();
}

---

you will notice that it works.

you could instead of declaring 9 separate variables just declare an array "board[3][3]", it would probably even facilitate the code when you implement a "check win condition" function.

edit: and you seem to know this since you used it for your second function, however for the 1st know that the local scope superseeds the global variables, I mean, if you name a global variable "TL" and then make a function void f1(char TL) inside that function TL means "the argument that was passed to me" so if you then call that function with a different argument, f1(TM) for example, it will do its operations with TM.
Worst of all, this is not a syntax error, so it will compile correctly, and it doesn't "look wrong" so it would be a great way for you to spend hours looking for a bug in a larger project simply because "TL is not TL inside that function"

---

In C++, remember to use std::string instead of char arrays and that main must return int. You cannot omit the return type of functions.

Ok, so I'm getting there after getting sidetracked with enums. I only have a few problems left now.

Code:

---

#include <iostream>

char gameBoard [3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}};

/*
 
 1,2,3
 4,5,6
 7,8,9
 
 [0][0], [0][1], [0][2]
 [1][0], [1][1], [1][2]
 [2][0], [2][1], [2][2]
 
 */

void printGameboard(); //no need to pass global variables as arguments to this function - info thanks to killme!
void resetGameboard();

int main()
{
   
    //variable to hold the 'X' for player 1, and 'O' for player 2
    char playerMarker;
   
    //the square a player chooses
    int squareChoice;
   
    //after game is finished, a choice for another go
    bool bAnotherGo = true;
   
    //main game loop - exits program if anotherGo is false
    do
    {
       
        bool bGameOver = false;
       
        //variable to switch whos turn it is (starts with player 1 == true)
        int playerTurn = 1;
       
        do //exits loop when the game is over i.e. true, then asks user if wants another go
        {
            //set markers for each player
            if (playerTurn == 1)
            {
                playerMarker = 'X';
            }
            else
            {
                playerMarker = 'O';
            }
       
            //prints game board with updated variables depending on player move
            printGameboard();
       
            //get player input
            std::cout << "Player " << playerTurn << ", your go: ";
            std::cin >> squareChoice;

            //check move is valid
            bool bIsValid;
       
            do
            {
                bIsValid = true;

                if (squareChoice == 1 && gameBoard[0][0] == '1')
                {
                    gameBoard[0][0] = playerMarker;
                }
                else if (squareChoice == 2 && gameBoard[0][1] == '2')
                {
                    gameBoard[0][1] = playerMarker;
                }
                else if (squareChoice == 3 && gameBoard[0][2] == '3')
                {
                    gameBoard[0][2] = playerMarker;
                }
                else if (squareChoice == 4 && gameBoard[1][0] == '4')
                {
                    gameBoard[1][0] = playerMarker;
                }
                else if (squareChoice == 5 && gameBoard[1][1] == '5')
                {
                    gameBoard[1][1] = playerMarker;
                }
                else if (squareChoice == 6 && gameBoard[1][2] == '6')
                {
                    gameBoard[1][2] = playerMarker;
                }
                else if (squareChoice == 7 && gameBoard[2][0] == '7')
                {
                    gameBoard[2][0] = playerMarker;
                }
                else if (squareChoice == 8 && gameBoard[2][1] == '8')
                {
                    gameBoard[2][1] = playerMarker;
                }
                else if (squareChoice == 9 && gameBoard[2][2] == '9')
                {
                    gameBoard[2][2] = playerMarker;
                }
                else
                {
                    std::cout << "Invalid Move. Try again: ";
                    std::cin >> squareChoice;
                    bIsValid = false;
                }
           
            } while (!bIsValid);

        //check to see if the previous move is a winning one
       
        if (!(gameBoard[0][0] == '1')) //if square 1 is not a number...
        {
            if (gameBoard[0][0] == gameBoard[0][1] && gameBoard[0][0] == gameBoard[0][2]) //3 in a row 1,2,3
            {
                bGameOver = true;
            }
           
            if (gameBoard[0][0] == gameBoard[1][0] && gameBoard[0][0] == gameBoard[2][0]) //3 in a row 1,4,7
            {
                bGameOver = true;
            }
        }
           
        if (!(gameBoard[1][1] == '5')) //if square 5 is not a number...
        {
            if (gameBoard[1][1] == gameBoard[0][1] && gameBoard[1][1] == gameBoard[2][1]) //3 in a row 2,5,8
            {
                bGameOver = true;
            }
           
            if (gameBoard[1][1] == gameBoard[1][0] && gameBoard[1][1] == gameBoard[1][2]) //3 in a row 4,5,6
            {
                bGameOver = true;
            }
           
            if (gameBoard[1][1] == gameBoard[0][2] && gameBoard[1][1] == gameBoard[2][0]) //3 in a row 7,5,3
            {
                bGameOver = true;
            }
           
            if (gameBoard[1][1] == gameBoard[0][0] && gameBoard[1][1] == gameBoard[2][2]) //3 in a row 1,4,9
            {
                bGameOver = true;
            }
        }
           
        if (!(gameBoard[2][2] == '9')) //if square 9 is not a number...
        {
            if (gameBoard[2][2] == gameBoard[2][1] && gameBoard[2][2] == gameBoard[2][0]) //3 in a row 7,8,9
            {
                bGameOver = true;
            }
           
            if (gameBoard[2][2] == gameBoard[1][2] && gameBoard[2][2] == gameBoard[0][2]) //3 in a row 3,6,9
            {
                bGameOver = true;
            }
        }
           
        //check for a tie
        // ??????????? //
           
           
        //congratulate player when game is over
        if (bGameOver == true)
        {
            std::cout << "Well done! Player " << playerTurn << " wins!" << std::endl;
        }
           
        //move is valid, switch players
        if (playerTurn == 1)
        {
            playerTurn = 2;
        }
        else
        {
            playerTurn = 1;
        }
       
        } while (bGameOver == false);
       
        //ask if they want another go? using while (bAnotherGo == 1) to exit loop and end game;
        std::cout << "Do you want another go? 1 for yes, 0 for no: ";
        std::cin >> bAnotherGo;
       
        //if they do want another go, reset the board, somehow...
        if (bAnotherGo == true)
        {
            resetGameboard();
        }
       
    } while (bAnotherGo == true);

std::cout << "I hope you enjoyed your game :)";
   
}

void printGameboard()
{
    for (int i = 0; i < 3; i++)
    {
        std::cout << "|" << gameBoard[i][0] << "|" << gameBoard[i][1] << "|" << gameBoard[i][2] << "|" << std::endl;
       
        if (i < 2)
        {
            std::cout << "+" << "-" << "+" << "-" << "+" << "-" << "+" << std::endl;
        }
    }
}

void resetGameboard()
{
    gameBoard [3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}}; //excess elements in scalar initializer??
}

---

My problems now are:

1) How to check for a tie - still trying to figure out the logic and where in the program to check this.
2) How to reset board, the way I tried failed miserably! Error posted in comments above.
3) Finding a way to use enums in this code.

Any hints are appreciated but maybe not on #1, I feel I should really be able to get that myself by now, after all, I know how to check for a win, halfway there! Thanks for any input.

Well, so first of, the way you go about it is a mess. And because it is a mess, you won't find how to use enums.
Consider this: we have a board of 9 squares, which can each contain circle, X or be empty. What is a good way to represent this in a computer?
How would you in reality go about checking if a move is valid, check for a winner or tie?

Also,
>>gameBoard [3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}}; //excess elements in scalar initializer??
Well, first off, you are trying to assign everything to one element which is out of bounds. How you can you assign 9 elements to one element?
If you removed the index subscript, used C++11 and std::array, you would get
gameBoard = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}}; //excess elements in scalar initializer??
which should work. But don't do that. This way of representing the board is just weird.

In reality, if I physically have a board in front of me, the squares are blank. I couldn't put a cross where there is already a cross. I couldn't put a circle where there is already a circle. I can only place a cross or circle on a blank square. I could use:

Code:

---

enum TicTacToeSquare {Blank, Circle, Cross};

TicTacToeSquare currentValue; //where currentValue holds 0,1 or 2

---

That makes sense to me in theory, but how do I translate that into a program? My squares have values, 1,2,3 etc... they are never empty.

It feels like I need to find a way that the printed numbers are just a representation of the board (so the user can pick a square) but the real values are simply 0,1 or 2 i.e. blank, cross or circle. I will keep working on this.

Why do your squares have numbered values? To me, each square is either a circle, X or empty.

Quote:

---

Originally Posted by Elysia

Why do your squares have numbered values? To me, each square is either a circle, X or empty.

---

You're right, in a real life scenario, but if I was playing this game online gor example, I would expect the squares to be numbered to show which one to choose. Rather that than choose a row 1-3, choose a column 1-3... that's just making things difficult for the player. I have seen both examples online and much prefer the former.

Quote:

---

That makes sense to me in theory, but how do I translate that into a program? My squares have values, 1,2,3 etc... they are never empty.

It feels like I need to find a way that the printed numbers are just a representation of the board (so the user can pick a square) but the real values are simply 0,1 or 2 i.e. blank, cross or circle. I will keep working on this.

---

so basicly the only thing that stands in the way of using enums as you want to is your printGameboard() function, if you start by rewriting it "enum-friendly" every thing else falls into place much easier.

Quote:

---

1) How to check for a tie - still trying to figure out the logic and where in the program to check this.

---

what do you mean "check for a tie", you are aiming to check if after some move in the middle of the game there is no longer anyway of one of the players winning? or would you be contempt with letting the board fill up completly? the questions themselfs answer the "where", as for the how.... well, the 2nd case is pretty straight forward, the 1st... what do YOU look at in a board to see if its a tie? (warning: implementing a function to do it this way will probably take you as long as the rest of the program combined)

Quote:

---

Originally Posted by samwillc

You're right, in a real life scenario, but if I was playing this game online gor example, I would expect the squares to be numbered to show which one to choose. Rather that than choose a row 1-3, choose a column 1-3... that's just making things difficult for the player. I have seen both examples online and much prefer the former.

---

yes but thats only an interface problem, you should try to separate in your head what data the program needs for running from what you want it to show on the screen. does it need 123456789 inside the data structure? can't you just "translate" the position?

Quote:

---

Originally Posted by killme

yes but thats only an interface problem, you should try to separate in your head what data the program needs for running from what you want it to show on the screen. does it need 123456789 inside the data structure? can't you just "translate" the position?

---

This.
You need to figure out how, given some input, you find the appropriate place which keeps that state in your program and modify it.
You are doing a rather poor job of that right now.

That sounds very ambiguous, doesn't it? So I'll give you an example.
Consider a weird calculator. It stores a set of 3 numbers, then allows you to sum, subtract, multiply or divide these numbers.
So you basically get a menu like:

- Enter a number
-- Store as number 1
-- Store as number 2
-- Store as number 3
-Add these numbers...
- ...

How would you store these numbers and find them later?

Quote:

---

Originally Posted by Elysia

This.
You need to figure out how, given some input, you find the appropriate place which keeps that state in your program and modify it.
You are doing a rather poor job of that right now.

---

I'm still working on arrays but let's just say I have a bunch of integers for now. This is how I imagine it working if this helps to clarify my position:

Board is blank, this is shown on screen:

| | | |
------
| | | |
------
| | | |
Enter 1-9 (have to figure out a way to present this i.e. data stored vs what's presented on screen. But for now, get the values stored correctly)

Player 1 is a cross, player 2 is a circle.

I have enums (0) blank, (1) cross, (2) circle.

int boardPos1 = blank;
int boardPos2 = blank;
int boardPos3 = blank;
int boardPos4 = blank;
int boardPos5 = blank;
int boardPos6 = blank;
int boardPos7 = blank;
int boardPos8 = blank;
int boardPos9 = blank;

If player 1 enters 6:

int boardPos6 = cross

If player 2 enters 9:

int boardPos9 = circle;

So I could use the new values to update the board:

int boardPos1 = blank;
int boardPos2 = blank;
int boardPos3 = blank;
int boardPos4 = blank;
int boardPos5 = blank;
int boardPos6 = cross
int boardPos7 = blank;
int boardPos8 = blank;
int boardPos9 = circle;

But wouldn't this just update the board like this:

| | | |
------
| | |1|
------
| | |0|

Once I store things in the proper place, I can see that the comparisons would all be pretty straightforward. However, I'm finding the bit in between step 1 and 3 rather more tricky. And perhaps this isn't the way to go about it anyway!

It's a pretty common subject, tic tac toe. I've written about it before, so I guess my advice is just to search harder.

There is no reason to check for a cat game before you fill all the squares though.

Quote:

---

Originally Posted by whiteflags

It's a pretty common subject, tic tac toe. I've written about it before, so I guess my advice is just to search harder.

There is no reason to check for a cat game before you fill all the squares though.

---

I will go away and research into this. I think otherwise this thread will go on forever.

I am aware that a game can be finished before all the squares are filled up but I had no idea what a 'cats game' was until I looked it up. We call this game noughts and crosses here, 'tic tac toe'?! :)

Will crack on later after work. Thanks.

Quote:

---

Originally Posted by samwillc

...

So I could use the new values to update the board:

int boardPos1 = blank;
int boardPos2 = blank;
int boardPos3 = blank;
int boardPos4 = blank;
int boardPos5 = blank;
int boardPos6 = cross
int boardPos7 = blank;
int boardPos8 = blank;
int boardPos9 = circle;

But wouldn't this just update the board like this:

| | | |
------
| | |1|
------
| | |0|

---

Now that just seems weird to me. I would have thought it would have updated the board like so:

| | | |
------
| | |X|
------
| | |O|

So that seems good. But there are two additional things. First, if you have variables BoardPos1...BoardPos9, what do you do? You merge them into an array, of course, where the index is the offset!
So, something like:

std::array<int, 9> BoardPos;

But it goes farther. An enum is not an int. It is a type where a variable of that type can only take the values stated in that enum.
(Yes, you can do implicit conversions between enums and ints, but get that out of your mind now.)
Therefore, this is wrong:

int boardPos9 = circle;

It should look something like

Code:

---

enum class BoardPos_t { X, O, Blank };
std::array<BoardPos_t, 9> BoardPos;
// Remember that arrays start from 0, so pos 6 = 5 from 0.
BoardPos.at(5) = BoardPos_t::X;
BoardPos.at(8) = BoardPos_t::O;

---

Read more about arrays: SourceForge.net: Safer arrays in Cpp - cpwiki

Quote:

---

Originally Posted by Elysia

Now that just seems weird to me. I would have thought it would have updated the board like so:

| | | |
------
| | |X|
------
| | |O|

---

Yes, this is how I would expect it too, so I need to find a way to show 0,1 or 2 as a 'X', 'O' or blank. I will look at your post in more detail later and practice more with arrays. I haven't actually done any work from my book on arrays so need to do that to get at least some basic understanding. Thanks for the help, I'll get there in the end, not giving up.

Why do you need to show 0, 1, 2, etc as X, O or blank? You use the offset inputted as the user to index yourself in the array.
Anyway, I would suggest you familiarize yourself with arrays before continuing tic-tac-toe. Be sure to read the link to know more about arrays (later), because I'm sure your book won't mention std::array.

Quote:

---

Originally Posted by Elysia

Why do you need to show 0, 1, 2, etc as X, O or blank? You use the offset inputted as the user to index yourself in the array.
Anyway, I would suggest you familiarize yourself with arrays before continuing tic-tac-toe. Be sure to read the link to know more about arrays (later), because I'm sure your book won't mention std::array.

---

I will look at the link :) and try to work this out.

Quote:

---

Originally Posted by Elysia

Why do you need to show 0, 1, 2, etc as X, O or blank?

---

1) If a user inputs a 4
2) int boardPos4 is updated to a circle (which is enum value 2);
3) If I now std::cout boardPos4 to show a circle on the board, it wont, it'll show a number 2 (the value of the enum)

That's how I see it. I don't know why this concept is so difficult for me, everything else was going ok so far!

In response to part of your edited out message:
Again, keep in mind that an enum is not an int! A value in an enum is not an int. It is not implicitly convertible to an int, so get that out of your mind (again, this is C++11 strongly typed enums; forget all other ones if you have a C++11 compiler). That means you cannot output an enum directly (you can't cout it), and an O is O and X is X, nothing else.

Sorry, I edited before you posted again.

Code:

---

enum TicTacToeSquare {circle, cross, blank}

---

Then what is the value of cross, circle, blank here?

*EDIT*

Forget that, saw your earlier post:

Code:

---

enum class BoardPos_t { X, O, Blank };

---

I will get back to this later.

You are using old enums. The syntax should be:

Code:

---

enum class TicTacToeSquare {circle, cross, blank}

---

Whatever "value" these have is irrelevant. It's just a state. How it's stored in computer memory doesn't matter.

Quote:

---

Originally Posted by Elysia

Code:

---

enum class BoardPos_t { X, O, Blank };
std::array<BoardPos_t, 9> BoardPos;
// Remember that arrays start from 0, so pos 6 = 5 from 0.
BoardPos.at(5) = BoardPos_t::X;
BoardPos.at(8) = BoardPos_t::O;

---

---

Ah, I think I see.

Code:

---

BoardPos.at(5) = BoardPos_t::X;

---

would be written instead of:

Code:

---

int boardPos4 = cross;

---

Now, I will look at that link later. There is one more thing that confuses me from Jumping Into C++

Code:

---

enum RainbowColor { //I know, should be class, taken from book as is
RC_RED, RC_ORANGE, RC_YELLOW, RC_GREEN, RC_BLUE, RC_INDIGO, RC_VIOLET
};

RainbowColor chosen_color = RC_RED;

---

If I can use:

Code:

---

//EXAMPLE A
BoardPos.at(5) = BoardPos_t::X;

---

this is using BoardPos_t directly so to speak, not a variable of BoardPos_t.

In the book, what is the point/s of having a variable of the new enum type (variable 'chosen_color' above) if you can access the enum values directly like in EXAMPLE A?

In other words, do you ever need a variable of your custom enum type in C++11? I hope this makes sense.

Thanks.

Quote:

---

Originally Posted by samwillc

If I can use:

Code:

---

//EXAMPLE A
BoardPos.at(5) = BoardPos_t::X;

---

this is using BoardPos_t directly so to speak, not a variable of BoardPos_t.

In the book, what is the point/s of having a variable of the new enum type (variable 'chosen_color' above) if you can access the enum values directly like in EXAMPLE A?

In other words, do you ever need a variable of your custom enum type in C++11? I hope this makes sense.

Thanks.

---

No, I think you are misunderstanding. BoardPos is an array of type BoardPos_t. A BoardPos_t can only take values that are available in the enum BoardPos_t. Furthermore, to access these values, you must specify the enum type, so you can't do

BoardPos.at(5) = X; // <--- compile error: "X" is undeclared.

Also, know that they are not implicitly convertible to any other type. So BoardPos must be declared as std::array<BoardPos_t, 8>, where the type BoardPos_t is important. Substitute it for anything else and you get a compile error.

I know this is going to cause confusion, so let me state this, as well. In previous versions of C++ (the old enums), you were allowed to do what I just did above (and also convert enums values to int and vice versa). To use these "old enums", you omit the keyword "class", so instead of "enum class", you write just "enum". Know that I do not recommend you do this. It is always better to use newer features, if possible. The older enums exist for backward compatibility.

Quote:

---

Originally Posted by samwillc

In other words, do you ever need a variable of your custom enum type in C++11? I hope this makes sense.

---

This has not much to do with the kind of enum you are using. That is to say the answer to the question that you are asking is as true for old enums as the new C++11 ones.

The short, simplest answer to your question is maybe. Now for the explanation:

For all intents and purposes BoardPos.at(5) is an expression for a variable of BoardPos_t. In the array data structure, all you have are variables of the same type, stored one after another ("contiguously") so that it is actually possible to refer to them individually by a number called a subscript. In C++ variables are usually objects. Sometimes they are references, but I don't want to talk about reference semantics. So until you learn about them, variables are objects is a true statement.

When you supply X to that part of the board like this:

BoardPos.at(5) = BoardPos_t::X;

You are assigning a value to an object, an array element. And as I explained before, the intent of array element is to be a numbered variable. In C++, understanding the difference between objects and values is important. It is the very foundation for more complex semantics (particularly the difference between r-values and l-values). Importantly, notice that objects are on the left of an assignment. By noting where they are, you get a beginner's perception of the difference between l-values and r-values: what in this expression is the object and where is the value that I am modifying it with.


[edit] As an aside, BoardPos is a deceptive name in my opinion, the array represents the board itself, not positions. [/edit]

Thanks for all the input. I have been busy the past few days and not had a chance to look at arrays. I will carry on over this weekend, then eventually get back to that tic tac toe game!