How can I get the created object of the class that is constructed in main() function?

Question

I want to get the object of the class which is constructed in main() function and use this object in another class.

This is the class I want to take the object of it:

typedef enum {
    DOWN = 1,
    LEFT = 2,
    UP = 3,
    RIGHT = 4
} tWaypointDir;

class Waypoint
{
    sf::Texture texture;
    sf::Sprite sprite;

public:
    float x, y;
    int dir;
    int next1, next2, next3;

    Waypoint(tWaypointDir dir, tRoadTileType type, int row, int col, int idx, int next1, int next2, int next3); // Constructor for the class.
    // idx: internal index of the waypoints, next1, 2, 3: next waypoints of the current one.
    // if there is only next1, next2 and next3 are -1. 
    int getNext(); //Get next waypoint randomly
    void getPosition(float &x, float &y, float &dir) const { x = this->x; y = this->y; dir = this->dir; }
    void setPosition(float x, float y, float dir) { this->x = x; this->y = y; this->dir = dir; }
    void draw(sf::RenderWindow *window) {window->draw(sprite);}
};

The object I created in the main() function is:

Waypoint waypoints[] = { //CTL: Road at top-left, HOR: horizontal, etc..
    {UP, CTL, 0, 0, 0, 1, -1, -1}, {RIGHT, CTL, 0, 0, 1, 0, -1, -1},
    {RIGHT, HOR, 0, 1, 0, 3, -1, -1}, {RIGHT, HOR, 0, 1, 1, 2, -1, -1},
    {RIGHT, TTOP, 0, 2, 0, 5, 6, -1}, {DOWN, TTOP, 0, 2, 1, 4, 6, -1},
    {RIGHT, TTOP, 0, 2, 2, 4, 5, -1}, {RIGHT, HOR, 0, 3, 0, 8, -1, -1}
};

Now, in the class Car, I want to use the waypoints[] object because I move the car in the direction of waypoints. I have a move() function in this class and I used this object in that part. We are not allowed to do the movement in main() function. Hence, I have to implement this in the class.

I tried the Singleton design pattern on the Waypoint class but it gives me errors on the constructor part. How can I implement this on the Car class?

Answer 1

You can pass pointer or reference on Waypoint class as argument in Car class constructor or method. Car class could store this reference or pointer as member. Then you can access this object from Car class