Polymorphism in C++ std::list<T>::iterator - c++

Question

Ignoring a lot of detail:
Suppose i have an abstract Card class containing the function:
virtual int getType()=0;
derived by the also abstract GreenCard in which there is a
virtual int getType()=0;
as well.
Then GreenCard is derived by non-abstract Follower and Item where the pure virtual is defined:
int getType(){ return 1;}
in the Follower class and
int getType(){ return 2;}
in the Item class.
Later i create (and fill) a list of GreenCard pointers
list<GreenCard*>* hand;
...i want to print the hand cards (depending on their types) in a loop:
list<GreenCard *>::iterator it;
for(it=hand->begin() ; it!=hand->end() ; ++i){
tp.getCorrectType(*it);
...
}
and in this function i get the SegFault in the first line!
void getCorrectType(GreenCard* card)
{
/*SF here->*/ if(card->getType()==2){
...
}
}
i am sure that the "card" is properly created and initialized because right in the previous line i write in the gdb: p *card
...and i can see all of its fields (Card, GreenCard and Item related ones-yes it is an 'item') beeing correct!
Edit: ok then heres some more code:
class Player{
list<GreenCard*>* fateDeck;
list<GreenCard*>* hand;
static const int START_HAND = 4;
Player(){
fateDeck = new list<GreenCard*> ();
hand = new list<GreenCard*>();
}
void initialize(){
DeckBuilder db;
*fateDeck = *(db.createFateDeck() );
db.deckShuffler(fateDeck);
initializeHand();
}
void initializeHand(){
for(int counter=0 ; counter<START_HAND ; counter++){
drawFateCard();
}
void drawFateCard(){
hand->push_front(fateDeck->front());
fateDeck->pop_front();
cout<<'\n'<<"Drawing from fate deck..."<<'\n'<<endl;
}
void Player::printHand(){
TypeConverter tp;
list<GreenCard *>::iterator it;
cout<<"You have " << hand->size()<<" fate cards in hand"<<'\n'
<<"They are the following:"<<endl;
for(it=hand->begin() ; it!=hand->end() ; ++it){
tp.getCorrectType(*it);
// printing depending on type
}
}
void startingPhase(){
printHand();
}
}
class DeckBuilder
{
private:
list<GreenCard*>* green;
public:
DeckBuilder();
list<GreenCard *>* createFateDeck();
void deckShuffler(list<GreenCard*>* green);
};
DeckBuilder :: DeckBuilder()
{
green = new list<GreenCard*>();
srand ( unsigned ( time (NULL) ) );
}
list<GreenCard *>* DeckBuilder :: createFateDeck()
{
int i;
for(i=0;i<40;i++) green->push_back(new Follower());
return green;
}
void DeckBuilder :: deckShuffler(list<GreenCard*>* green)
{
vector<GreenCard *> vect;
list<GreenCard*> ::iterator it;
for(it = green->begin();it!=green->end();it++)
vect.push_back((*it));
random_shuffle ( vect.begin(), vect.end() );
green->clear();
vector<GreenCard*>:: iterator it2;
for(it2 = vect.begin();it2!=vect.end();it2++)
green->push_back((*it2));
}
and eventually in main()
Player pl();
pl.initialize();
pl.startingPhase;
and segfaults in printHand();

Answer 1

I've pieced together the information you've given me. This compiles and runs without segmentation faults (using Visual Studio 2013):
#include "stdafx.h"
#include <algorithm>
#include <iostream>
#include <vector>
#include <list>
#include <ctime>
using namespace std;
class Card
{
public:
virtual int getType() = 0;
};
class GreenCard : public Card
{
public:
virtual int getType() = 0;
};
class Follower : public GreenCard
{
public:
int getType(){ return 1; }
};
class Item : public GreenCard
{
public:
int getType(){ return 2; }
};
class TypeConverter
{
public:
void getCorrectType(GreenCard* card)
{
if (card->getType() == 1)
std::cout << "Follower" << std::endl;
if (card->getType() == 2){
std::cout << "Item" << std::endl;
}
}
};
class DeckBuilder
{
private:
list<GreenCard*>* green;
public:
DeckBuilder();
list<GreenCard *>* createFateDeck();
void deckShuffler(list<GreenCard*>* green);
};
DeckBuilder::DeckBuilder()
{
green = new list<GreenCard*>();
srand(unsigned(time(NULL)));
}
list<GreenCard *>* DeckBuilder::createFateDeck()
{
int i;
for (i = 0; i < 40; i++) green->push_back(new Follower());
return green;
}
void DeckBuilder::deckShuffler(list<GreenCard*>* green)
{
vector<GreenCard *> vect;
list<GreenCard*> ::iterator it;
for (it = green->begin(); it != green->end(); it++)
vect.push_back((*it));
random_shuffle(vect.begin(), vect.end());
green->clear();
vector<GreenCard*>::iterator it2;
for (it2 = vect.begin(); it2 != vect.end(); it2++)
green->push_back((*it2));
}
class Player{
public:
list<GreenCard*>* fateDeck;
list<GreenCard*>* hand;
static const int START_HAND = 4;
Player(){
fateDeck = new list<GreenCard*>();
hand = new list<GreenCard*>();
}
void initialize(){
DeckBuilder db;
*fateDeck = *(db.createFateDeck());
db.deckShuffler(fateDeck);
initializeHand();
}
void initializeHand(){
for (int counter = 0; counter < START_HAND; counter++){
drawFateCard();
}
}
void drawFateCard(){
hand->push_front(fateDeck->front());
fateDeck->pop_front();
cout << '\n' << "Drawing from fate deck..." << '\n' << endl;
}
void Player::printHand(){
TypeConverter tp;
list<GreenCard *>::iterator it;
cout << "You have " << hand->size() << " fate cards in hand" << '\n'
<< "They are the following:" << endl;
for (it = hand->begin(); it != hand->end(); ++it){
tp.getCorrectType(*it);
// printing depending on type
}
}
void startingPhase(){
printHand();
}
};
int _tmain(int argc, _TCHAR* argv[])
{
Player pl;
pl.initialize();
pl.startingPhase();
return 0;
}
Please provide a small, stand-alone example that demonstrates the error.