unhandled exception

[Juan52]

Hey everyone I'm working on a Doubly linked list for my comp sci class, its coming along well but I keep getting this error: "Unhandled exception at 0x00B547E9 in Project2.exe: 0xC0000005: Access violation reading location 0xCCCCCCD0."

program name for now is program 2.

here is the code I have so far. I havent split it into header files yet so it a little lengthy.

#include <iostream>
#include <cstdlib>
#include <string>

using namespace std;

 class node
 {
	 friend class list;

 public:
	 int data;
	 node* next;
	 node* prev;
	

 };


 class list
 {
	 friend class node;

 public:
	 node* head;
	 node* tail;

	 void addright(int);
	 void addleft(int);
	 int asker();
	 int printl();
	 //list();
 };

/* list::list()
 {
	 head->next = NULL;
	 tail->prev = NULL;
 }*/




  
  string x;
  int a;
  
  

  int list::asker()
  {
	 
	  cout << "list> ";
	  cin >> x;
 
	  if(x == "addleft") {cin >> a; addleft(a);}
	  else
	  if(x == "addright") {cin >> a; addright(a);}
	  else
	  if(x == "quit") return 0;
	 
	  



  return 1;
  }
  void list::addleft(int a)
  {
	   node* temp = new node;
	  
	   temp->data = a; 
	 
	   if(head->next == NULL)
	{

	   head->next = temp;
	   temp->prev = head;
	   tail->prev = temp;
	   temp->next = tail;
	   return;
    }
    
	node* c;
	c = head;
	head->next = temp;
	temp->next = c->next;
	temp->prev = head;
	c = c->next;
	c->prev = temp;


  }
  void list::addright (int a)
 {

	
	 
	 

 }

  int list::printl()
  {
	  node* c;

	  c = head->next;
	  if(c == NULL){ cout << "Error!"; return 0;}
	  else while(c->next != NULL)
		  cout << c->data;
	  c = c->next;

	  return 0;
  }



 int main()
 {  
    list my_list;
	int num = 1;
 
	do
	{
		num = my_list.asker( );
	} while(num); 



	return 0;
 }

thanks for any help you can offer

[LB]

0xCCCCCCD0 looks like an offset of 0xCCCCCCCC, which is what MS compilers set uninitialized data to in debug mode. This means you are trying to dereference an uninitialized pointer.

[naraku9333]

This if(head->next == NULL) is a problem if head is null.