Singleton pattern used on another class - c++

Question

So I am trying to implement a program that has a scoreboard and two players, I am trying to make it so that the two players share a scoreboard using the singleton pattern. However when I try to use methods on the global scoreboard defined in the player classes I always get a "run failed" message.
These are my two header files, I can provide the full implementation if it's necessary.
#ifndef PLAYER_H
#define PLAYER_H
#include "scoreboard.h"
#include <string>
#include <fstream>
class Player{
private:
std::ifstream file1;
std::ifstream file2;
static Scoreboard* _game;
public:
static Scoreboard* Game();
void makeMove(const char,const std::string);
};
#endif
#ifndef SCOREBOARD_H
#define SCOREBOARD_H
class Scoreboard{
private:
int aWin;
int bWin;
int LIMIT;
int curCounter;
public:
void resetWins();
void addWin(char);
void makeMove(const int, char);
void startGame(const int, const int);
int getWin(char);
int getTotal();
int getLimit();
};
#endif /* SCOREBOARD_H */
in player.cc
Scoreboard* Player::_game = 0;
Scoreboard* Player::Game(){
if (_game = 0)
{
_game = new Scoreboard;
_game->resetWins();
}
return _game;
}
Along with the makeMove method

Answer 1

Your Scoreboard instance does not need to be a pointer:
static Scoreboard _game;
// ...
static Scoreboard& Game() { return _game; }
Or alternatively, just leave out the class declaration of _game:
// you can either make this function static or non-static
Scoreboard& Game()
{
static Scoreboard game; // but this variable MUST be static
return game;
}
That will do the same thing without the memory management issues.
This will create a single instance of Scoreboard for all Players. If you only ever wanted to have a single instance of Scoreboard (e.g. if you had a Referees class that needed to see the scoreboard as well), you would modify your scoreboard class:
class Scoreboard
{
private:
// all your data members
Scoreboard() {} // your default constructor - note that it is private!
public:
// other methods
Scoreboard& getInstance()
{
static Scoreboard instance;
return instance;
}
};
Then, to access it in your other classes, you would include the scoreboard header and use it as:
#include "Scoreboard.h"
void my_func()
{
Scoreboard& scoreboard = Scoreboard::getInstance();
scoreboard.DoSomething();
}

Answer 2

In Player::Game, you have written
if (_game = 0)
that is setting _game = 0 and evaluating to false, so that you don't actually create the scoreboard. Change it for:
if (_game == 0)