Not able to modify class composite data members - c++

Question

I have 3 classes in my program that interact with each other and contain each other's instances:
class Inventory
{
public:
// Increment Data Members
void incrementHerbs() { herbs++; }
void incrementHealth() { health++; }
void incrementGold() { gold++; }
// Getters
int getHerbs() { return herbs; }
int getHealth() { return health; }
int getGold() { return gold; }
private:
int herbs = 0;
int health = 3;
int gold = 0;
};
class Player
{
public:
void setRow(int row) { this->rowCoordinate = row; }
void setCol(int col) { this->colCoordinate = col; }
int getRow() { return rowCoordinate; }
int getCol() { return colCoordinate; }
Inventory getBag() { return Bag; }
private:
int rowCoordinate;
int colCoordinate;
Inventory Bag;
};
class Board
{
public:
int getNumRows() { return numRows; }
int getNumCols() { return numCols; }
Player getPlayer() { return User; }
private:
int numRows;
int numCols;
char** maze;
Player User;
};
I am only instantiating a Board object in the main function. At a point in my program, I want to be able to increment the herb count in the inventory class through that object.
I have tried doing:
Board board;
board.getPlayer().getBag().incrementHerbs();
This call compiles without any errors but when I print out the herb count afterwards, the herb count is still the same.
It did not increment. What can be going wrong and what can I do?

Answer 1

What can be going wrong and what can I do?
In your Player class, your getBag() function returns a copy of Inventory (i.e. member Bag).
Inventory getBag() { return Bag; }
//^^^^^^----> is copy!
You need to return the reference in order to modify it
Inventory& getBag() { return Bag; }
//^^^^^^^^
The same issue with the Board's function getPlayer()
Player getPlayer() { return User; }
//^^^^----> is copy!
you need
Player& getPlayer() { return User; }
//^^^^^^
And here's a demo.