I need help to add an m_pTail pointer data member to the Lobby class that always points to the last player node in the line and use it to more efficiently add a player.
//Game Lobby
//Simulates a game lobby where players wait
#include <iostream>
#include <string>
usingnamespace std;
class Player
{
public:
Player(const string& name = "");
string GetName() const;
Player* GetNext() const;
void SetNext(Player* next);
private:
string m_Name;
Player* m_pNext; //Pointer to next player in list
};
Player::Player(const string& name):
m_Name(name),
m_pNext(0)
{}
string Player::GetName() const
{
return m_Name;
}
Player* Player::GetNext() const
{
return m_pNext;
}
void Player::SetNext(Player* next)
{
m_pNext = next;
}
class Lobby
{
friend ostream& operator<<(ostream& os, const Lobby& aLobby);
public:
Lobby();
~Lobby();
void AddPlayer();
void RemovePlayer();
void Clear();
private:
Player* m_pHead;
};
Lobby::Lobby():
m_pHead(0)
{}
Lobby::~Lobby()
{
Clear();
}
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;
}
int main()
{
Lobby myLobby;
int choice;
do
{
cout << myLobby;
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 << endl << "Enter choice: ";
cin >> choice;
switch (choice)
{
case 0: cout << "Good-bye.\n"; break;
case 1: myLobby.AddPlayer(); break;
case 2: myLobby.RemovePlayer(); break;
case 3: myLobby.Clear(); break;
default: cout << "That was not a valid choice.\n";
}
}
while (choice != 0);
return 0;
}
The question is ...Which sections of this do I need to modify and HOW do I make the pointer always point to the last player node?
Thank you in advance... I really want to understand this but am at a complete loss as to where to begin.
declare a variable m_pTail in Lobby class of type Player* . initially set this variable to 0.
whenever you add a player at end st this m_pTail pointer to that player.
your Lobby::AddPlayer fuction will also change as it has to just refer m_pTail pointer to get at last player nad add next plater to it.
class Lobby
{
friend ostream& operator<<(ostream& os, const Lobby& aLobby);
public:
Lobby();
~Lobby();
void AddPlayer();
void RemovePlayer();
void Clear();
private:
Player* m_pHead;
Player* m_pLast;
};
Lobby::Lobby():
m_pHead(0) , m_pLast(0)
{}
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);
pIter = pIter->GetNext();
m_pLast = pIter;
}
}
