Please help with this merchant class.

class merchant
{
public: 
  merchant(); //merchant constructor
  
  ~merchant(); //merchant destructor
 
  int sell(int x, int y);
  int buy (int p, int q);
  void balance ();
};

merchant::merchant()
{
  //need to initialize to 1000???
}

merchant::~merchant()
{
  //destructor accepting no arguments.
}

int merchant::sell (int x, int y)
{
  ///should implement here, ..calls the sell member function which will sell a certain amount of what it has to the other merchant which is what?    
  ///// return something?
}

int merchant::buy (int p, int q)
{
  ///should implement here, could be similiar to the sell member function. 
  
      // return something?
}

void merchant::balance()
{
  // this should probably be an integer return type, but how??
}

int main(){ 
  merchant a, b, c; 
  a.sell(50,b); 
  a.sell(c,50); 
  c.buy(70,b); 
  a.balance(); 
  b.balance(); 
  c.balance(); 
  return 0; 
} 

class merchant
{
private:
  int stock;
public: 
  merchant(); //merchant constructor
  
  ~merchant(); //merchant destructor
 
  void sell(int x, merchant& y);
  void sell(merchant& y, int x) { sell(x,y); }
  // Same needs to happen with buy  
  int buy (int p, int q);

  void balance() { std::cout << stock;  }
};

merchant::merchant()
{
  //need to initialize to 1000???
  stock=1000;
}