Member not declared in scope? - c++

Question

So I'm trying my hand at some C++ after finishing up an introductory book, and I've become stuck. I've made a vector of objects that each have an SFML circle object as a member, and I want main() to go and draw these circles. The vector is called theBoard, but when I try to access it, I get the following error messages:
error: request for member 'theBoard' in 'GameBoard', which is of non-class type 'Board*'
error: 'theBoard' was not declared in this scope
I'm new to this (came from two years of Python), so I'm sure I made a mistake somewhere. Here is the relevant code for the board creation:
class Board
{
public:
//These are the member functions.
Board();
~Board();
vector<Space*> CreateBoard();
//This will be the game board.
vector<Space*> theBoard;
//These clusters represent the waiting areas for pieces not yet in the game.
vector<Space*> Cluster1;
vector<Space*> Cluster2;
vector<Space*> Cluster3;
private:
//These integers represent the number of spaces on each row, starting at the top (which is row [0])
vector<int> RowNums;
};
Board::Board()
{
//Fill in RowNums with the right values.
RowNums.push_back(1);
RowNums.push_back(17);
RowNums.push_back(2);
RowNums.push_back(17);
RowNums.push_back(1);
RowNums.push_back(1);
RowNums.push_back(5);
RowNums.push_back(2);
RowNums.push_back(7);
RowNums.push_back(2);
RowNums.push_back(11);
RowNums.push_back(3);
RowNums.push_back(17);
RowNums.push_back(4);
RowNums.push_back(17);
//Then, create the board.
theBoard = CreateBoard();
}
CreateBoard() is a very, very long function that returns a vector of pointers to Space objects. I doubt there's a problem here, as the only error message I get crops up when I try to access the circle members of Space objects in main(). It seems to me as though I have declared theBoard in the relevant scope, that is, as a data member of the Board class.
My main() function, in case it's important:
int main()
{
//This sets up the display window.
sf::RenderWindow App(sf::VideoMode(1200, 900, 32), "Malefiz");
//This creates the board on the heap, and a pointer to it.
Board* GameBoard = new Board();
cout << "Board made.";
//This is the game loop.
while(App.IsOpened())
{
//This is used to poll events.
sf::Event Event;
while(App.GetEvent(Event))
{
//This closes the window.
if(Event.Type == sf::Event::Closed)
{
App.Close();
}
}
//This gets the time since the last frame.
//float ElapsedTime = App.GetFrameTime();
//This fills the window with black.
App.Clear(sf::Color(200, 200, 125));
//This draws the places into the window.
for(int i = 0; i < GameBoard.theBoard.size(); ++i)
{
App.Draw(GameBoard.*theBoard[i].m_Circle);
}
//This displays the window.
App.Display();
}
return EXIT_SUCCESS;
}

Answer 1

In your main() function, GameBoard is a Board *, not a Board. So to access members, you need to use -> instead of .. e.g.:
GameBoard->theBoard.size()
[Some people (I am one of them) like to name their pointer variables with a leading p or ptr prefix, in order to make this kind of irritation explicitly clear.]

Answer 2

GameBoard is a pointer to a Board object, and thus you need to use the "->" operator instead of the "." operator to access any of its member variables or methods.

Answer 3

The error is quite explicit if you read it carefully:
error: request for member 'theBoard' in 'GameBoard', which is of non-class type 'Board*'
error: 'theBoard' was not declared in this scope
The first line is telling you that you have a pointer to a Board object and you are trying to access a member directly. That is:
Board *p = ...
p.theBoard; // Error, should be p->theBoard, as p is a pointer
Also note that GameBoard.*theBoard[i].m_Circle might not be what you want, you probably want (I am guessing as there are important bits missing) something like GameBoard->theBoard[i]->m_Circle.

Answer 4

GameBoard is a pointer, so the syntax should be this:
for(int i = 0; i < GameBoard->theBoard.size(); ++i)
{
App.Draw((GameBoard->theBoard[i])->m_Circle);
}
Since elements of theBoard also are pointer, so I used the pointer notation when accessing m_Circle.