C ++ double pointer access

Question

Question about C ++ (Arduino wrapper): I'm writing a shoot for an Arduino game that has an LCD connected to it -

I have a base class ( Sprite), and other classes - Alien, Missileand are derived from this Player. The Alien class constructor also has a private member pMissile(a pointer to the class Missile) - an “object inside an object” would be a way to describe this, I think. [when a Alienlaunches a rocket, it passes its own (x, y) coordinates to the rocket, and the rocket has its own way of moving, starting from the coordinates Alien]

My question is: how can I access the coordinates of a rocket through an object Alien? The ordered code is below, and I also drew a representation of the classes:

// Bass class - has a form/shape, x and y position  
class Sprite
{
  public:
    Sprite(unsigned char * const spacePtrIn, unsigned int xInit, unsigned int yInit);
    virtual void Move() = 0;
    void Render() { display.drawBitmap(x,y, spacePtr, 5, 6, BLACK); }
    unsigned int getX()    const { return x; } 
    unsigned int getY()    const { return y; }
  protected:
    unsigned char *spacePtr;
    unsigned int x, y;
};


// Derived class "Missile", also a sprite and has a specific form/shape, and specific (x,y) derived from input sprite
class Missile : public Sprite
{
public:
   Missile(): Sprite(&spaceMissile[0], 0, 0) {}
   virtual void Move();  // its own method of moving
};

// Derived class "Alien" - has a specific form/shape, and specific (x,y) position
class Alien : public Sprite
{
public:
   Alien(); 
   virtual void Move();   // its own method of moving
private:
   Missile *pMissile;
};

Alien::Alien(): Sprite(&spaceAlien[0], random(5, 75), random(4, 10))
{
  Missile MissileArray[MaxAmmoSize];
  pMissile = &MissileArray[0];
}


void Alien::Move()
{ 
  if( random(10) % 2 == 0 )
    x += 1;
  if( random(10) % 3 == 0 )
    y += 1;

  if( (pMissile != NULL) && (random(10) == 1) )
  {
    pMissile->setCoord(x, y);
    pMissile->Move();  // move the missile   
    pMissile++;        // move onto the next missile in the array
  }
  Render();
}

/*****************************************************************************************/
Alien MONSTER;
Player HERO;
Alien *pMONSTER = &MONSTER;

void loop()
{
  display.clearDisplay();
  MONSTER.Move();
  HERO.Move(); 
  pMONSTER->getX(); // this is x location of MONSTER
  **// how does pMONSTER access pMissile(x,y) within MONSTER.** 
  delay(100);
  display.display();
}

++-

Answer 1

getter Alien:

class Alien {
public:
    Missile* getMissile() { return pMissile; }
}

:

Alien* a = getAlienFromSomewhere();
auto pMissile = a.GetMissile();
if (pMissile != NULL) {
    x = pMissile->getX();
    y = pMissile->getY();
}

Answer 2

, , , , "" , Alien::Move(). .

, - :

// Bass class - has a form/shape, x and y position  
class Sprite
{
  public:
    Sprite(unsigned char * const spacePtrIn, unsigned int xInit, unsigned int yInit);
    virtual void Move() = 0;
    void Render() { display.drawBitmap(x,y, spacePtr, 5, 6, BLACK); }
    unsigned int& getX()    const { return x; } 
    unsigned int& getY()    const { return y; }
  protected:
    unsigned char *spacePtr;
    unsigned int x, y;
};


// Derived class "Missile", also a sprite and has a specific form/shape, and specific (x,y) derived from input sprite
class Missile : public Sprite
{
public:
   Missile(): Sprite(&spaceMissile[0], 0, 0) {}
   virtual void Move();  // its own method of moving
};

// Derived class "Alien" - has a specific form/shape, and specific (x,y) position
class Alien : public Sprite
{
public:
   Alien(); 
   ~Alien(); // a destructor to cleanup your missiles - arduino have almost no memory to handle leaks ;-) 
   virtual void Move();   // its own method of moving

   inline Missile& getMissile(unsigned char n) { return pMissile[n];          }
   inline Missile& operator[](unsigned char n) { return getMissile(n);        }
   inline unsigned int& getX(unsigned char n)  { return getMissile(n).getX(); }
   inline unsigned int& getY(unsigned char n)  { return getMissile(n).getY(); }

private:
   Missile *pMissile;
   // adding the code to handle the count
   unsigned char missileCount;
};

Alien::Alien(): 
  Sprite(&spaceAlien[0], random(5, 75), random(4, 10)),
  missileCount(0)
{
  // this way of allocation creates a local object that is destroyed by the end of this scope
  //Missile MissileArray[MaxAmmoSize];
  //pMissile = &MissileArray[0];

  // so you should do somethin like this
  pMissile = new Missile[MaxAmmoSize];
}

Alien()::~Alien()
{
  delete[] pMissile;
}

void Alien::Move()
{ 
  if( random(10) % 2 == 0 )
    x += 1;
  if( random(10) % 3 == 0 )
    y += 1;

  if( (pMissile != NULL) && (random(10) == 1) )
  {
    // my proposal to fire it up
    Missile& missile = pMissile[missileCount];
    missile->setCoord(x, y);
    missile->Move();  // move the missile   
    missileCount++;   // move onto the next missile in the array
  }
  Render();
}

, , :

MONSTER.getX(0) += 1;
MONSTER[0].getY() +=1;
MONSTER.getMissile(1).getX() = 10;

getX() getY() x() y(), ( x y - , ).