Help Copy Constructor

Lobby& operator=(const Lobby& aLobby)	{		if (this == &aLobby) 		{			return *this;		}		else		{			*m_pHead = aLobby.GetPlayer();			return *this;		}	}

// Game Lobby 2.0 Exersize Enhancements// Simulates a game lobby where players wait#include <iostream>#include <string>using std::cout;using std::cin;using std::endl;using std::string;using std::ostream;class Player{public:	Player(const string& name = "") : m_Name(name), m_pNext(0) {}	string GetName() const {return m_Name;}	Player* GetNext() const {return m_pNext;}	void SetNext(Player* next) {m_pNext = next;}private:	string m_Name;	Player* m_pNext;	// pointer to the next player in list};class Lobby{	friend ostream& operator<<(ostream& os, const Lobby& aLobby);public:	Lobby(): m_pHead(0) {}	~Lobby() {Clear();}	void AddPlayer();	void RemovePlayer();	void Clear();	Player GetPlayer() const {return *m_pHead;}	Lobby& operator=(const Lobby& aLobby)	{		if (this == &aLobby) 		{			return *this;		}		else		{			*m_pHead = aLobby.GetPlayer();			return *this;		}	}	Lobby(const Lobby& aLobby)		// Copy Constructor	{			cout << "Copy Constructor Called...\n\n";		m_pHead = 0;		*m_pHead = aLobby.GetPlayer();	}	private:	Player* m_pHead;};void Lobby::AddPlayer(){	// create a new player node	cout << "Please enter the name of the new player: ";	string name;	cin >> name;	Player* pNewPlayer = new Player(name);	// if list is empty, make head of list this new player	if (m_pHead == 0) 	{		m_pHead = pNewPlayer;	}	// otherwise find the end of the list and add the player there	else	{		Player* pIter = m_pHead;		while (pIter->GetNext() != 0)		{			pIter = pIter->GetNext();		}		pIter->SetNext(pNewPlayer);	}}void Lobby::RemovePlayer(){	if (m_pHead == 0) 	{		cout << "The game lobby is empty. No one to remove!\n";	}	else	{		Player* pTemp = m_pHead;		m_pHead = m_pHead->GetNext();		delete pTemp;	}}void Lobby::Clear(){	while (m_pHead != 0)	{		RemovePlayer();	}}ostream& operator<<(ostream& os, const Lobby& aLobby){	Player* pIter = aLobby.m_pHead;	os << "\nHere's who's in the game lobby:\n";	if (pIter == 0) 	{		os << "The lobby is empty.\n";	}	else	{		while (pIter != 0)		{			os << pIter->GetName() << endl;			pIter = pIter->GetNext();		}	}	return os;}void testCopy(Lobby aLobby);int main(){	Lobby mLobby;	int choice;	do {		cout << mLobby;		cout << "\nGame Lobby\n";		cout << "0 - Exit the program.\n";		cout << "1 - Add a player to the lobby\n";		cout << "2 - Remove a player from the lobby.\n";		cout << "3 - Clear the lobby.\n";		cout << "4 - Copy the Lobby.\n";		cout << endl << "Enter choice: ";		cin >> choice;		switch(choice)		{		case 0: cout << "Good-Bye\n"; break;		case 1: mLobby.AddPlayer(); break;		case 2: mLobby.RemovePlayer(); break;		case 3: mLobby.Clear(); break;		case 4: testCopy(mLobby); break;		default: cout << "That was not a valid choice.\n";		}	} while(choice != 0);	return 0;}void testCopy(Lobby aLobby){	cout << "Copy Complete?\n\n";	cout << aLobby;}

Player& Player::operator= (const Player& other) {  // We need to make a copy of the subsequent players, as well - this happens  // recursively; our base case is when the m_pNext is null.  m_Name = other.m_Name; // the std::string copy ctor and assignment op already  // work the way we want them to :)  // Before we can copy subsequent players, we need to remove any Players the  // current object might already be pointing at:  delete m_pNext; // this is ok whether NULL or not.  // We do this even if there are no players in the other list, so that the  // lists end up being the same.  if (other.m_pNext) {    // then there is a list of players to copy.     // Now we point our player list at a copy of the other player list. Since    // we don't have a valid object to assign into, we have to use the copy    // constructor on the "next" Player of the other:    m_pNext = new Player(*(other.m_pNext));  } }

// First attempt:Player::Player (const Player& other) {  // Here is our code to copy a Player.  // First, copy the name:  m_Name = other.m_Name;  // and now, copy the subsequent players. Since 'this' is a new Player, we  // know there isn't anything in m_pNext that needs to be cleaned up.  if (other.m_pNext) {    m_pNext = new Player(*(other.m_pNext));  } else {    m_pNext = 0; // make sure it's nulled out.  }}// That's not ideal, though: we're only setting data members, so we really// ought to use an initializer list. Here's one place in C++ where the ternary// op really comes in handy ;)Player::Player (const Player& other) : m_Name(other.mName),  // Recursively copy if not null.  m_pNext(other.m_pNext ? new Player(*(other.m_pNext)) : 0) {}// No code within the function any more. :)// Ok, now that we have a nice, neat copy constructor, let's make a nice, neat// assignment operator to go with it, via the copy-and-swap idiom:Player& Player::operator= (const Player& other) {  Player tmp(other);  std::swap(*this, other);  return *this;}

Player::~Player() {  // If the pointer is null, we're done. Otherwise, we need to delete the  // player that we point at. Of course, that will trigger the destructor for  // that Player, and so on, recursively. Which is all as it should be. Oh, and  // since deleting a null pointer is safe (and does nothing), all we really  // need is:  delete m_pNext;  // If you can't convince yourself that this works, go read up on recursion,  // and try again. :)}