Boolean, what does it return?

This is a discussion on Boolean, what does it return? within the C++ Programming forums, part of the General Programming Boards category; I've just started my C++ class and I'm starting my first program: TicTacToe. My professor posted some hint code to ...

  1. #1
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    Arrow Boolean, what does it return?

    I've just started my C++ class and I'm starting my first program: TicTacToe. My professor posted some hint code to help us out, and one thing he used was a function bool validmove(). I'm trying to write out the function, but I'm not sure what bool does.
    Does bool return only TRUE and FALSE? Any help would be appreciated, thanks.

  2. #2
    Veni Vidi Vice
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    Yes thats correct, bool returns true or false

  3. #3
    &TH of undefined behavior Fordy's Avatar
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    One small point that may cause a problem....may not....

    C++ defines the type "bool" which can be "true" or "false"

    Windows defines the type "BOOL" which can be "TRUE" or "FALSE"

    Looking at a little dissasembly;

    BOOL B;

    bool b;

    B = TRUE; //mov dword ptr [ebp-4],1

    b = true; //mov byte ptr [ebp-8],1
    Notice that the c++ version is addressed as a BYTE (8bit) in memory, but the Windows version is addressed as a DWORD (32bit)........

    They both do the same thing thing......but mixing them can lead to problems...so if your code uses bool, use true & false as opposed to TRUE & FALSE

  4. #4
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    Ok, thanks for the confirmation on bool.

    Another thing, I comliled some code that I wrote, and I get an error message saying: "subscript requires array or pointer type."

    What does this mean?

  5. #5
    Veni Vidi Vice
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    Post code please.

  6. #6
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    Oh sorry, I didn't realize I left it out.

    This is the function that has the problems:

    TicTacToe::Status TicTacToe::gamestatus(void)
    {
    int a, c, r;

    // check for a win on diagonals
    if (board[0] != ' ' && board[0] == board[4] && board[0] == board[8])
    return WIN;
    else if (board[2] != ' ' && board[2] == board[4] && board[2] == board[6])
    return WIN;

    // Check for a win across top row
    if(board[0] != ' ' && board[0] == board[1] && board[0] == board[2])
    return WIN;
    //Check for a win across middle row
    if(board[3] != ' ' && board[3] == board[4] && board[3] == board[5])
    return WIN;
    //Check for a win across bottom row
    if(board[6] != ' ' && board[6] == board[7] && board[6] == board[7])
    return WIN;
    //Check for a win down left column
    if(board[0] != ' ' && board[0] == board[3] && board[0] == board[6])
    return WIN;
    //Check for a win down middle column
    if(board[1] != ' ' && board[1] == board[4] && board[1] == board[7])
    return WIN;
    //Check for a win down right column
    if(board[2] != ' ' && board[2] == board[5] && board[2] == board[8])
    return WIN;

    //Check for game completion
    for(c=0; c<9; ++c)
    if (board[r] == ' ')
    return CONTINUE; // Game is not finished

    return DRAW; // Nothing matches, game is a draw.
    }

  7. #7
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    Next time you post code use code tags please.

    Im not sure you can do like this, I assume that theese functions
    do the same thing, use one function only. Also should it return a datatype which is the same as WIN, CONTINUE and DRAW
    Code:
    TicTacToe::Status TicTacToe::gamestatus(void)
    Code:
    int a,c,r;
    You should always assign a value to a varible before you use it. Varible a is unneccesary and r contain garbage-value which mean that you dont compare the array correctly.

    Code:
    for(c=0; c<9; ++c)
    if (board[r] == ' ')
    return CONTINUE; // Game is not finished
    Should be if (board[i] == )

    Make also sure that the function returns the right datatype.

    Hope that helps!

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