list.h

practice c++, it is from the book http://www.amazon.com/Schaums-Outline-Programming-John-Hubbard

//  Programming with C++, Second Edition, by John R. Hubbard
//  Copyright McGraw-Hill 2000
//  List.h
//  A List Class Template

template <class T>
class ListNode
{ friend class ListIter<T>;
  friend class List<T>;
public:
  ListNode(T& t, ListNode<T>* p) : data(t), next(p) { }
protected:
  T data;          // data field
  ListNode* next;  // points to next node in list
};

template<class T>
class List
{ friend class ListIter<T>;
public:
  List() : first(0) { }
  ~List();
  void insert(T t);                    // insert t at front of list
  int remove (T& t);                   // remove first item t in list
  bool isEmpty() { return (first==0); }
  void print();
protected:
  ListNode<T>* first;
  ListNode<T>* newNode(T& t, ListNode<T>* p)
  { ListNode<T>*q = new ListNode<T>(t,p); return q; }
};

template<class T>
List<T>::~List()
{
  ListNode<T>* temp;
  for (ListNode<T>* p = first; p; )   // traverses list
    {
      temp = p;
      p = p->next;
      delete temp;
    }
}

template<class T>
void List<T>::insert(T t)
{
  ListNode<T>* p = newNode(t, first);
  first = p;
}

template<class T>
int List<T>::remove(T& t)
{
  if (isEmpty()) return 0;   // flag to signal no removal
  t = first->data;           // data value returned by refrence
  ListNode<T>* p = first;
  first = first->next;       // advance first pointer to remove node
  delete p;
  return 1;                  // flag to signal successful removal
}

template<class T>
void List<T>::print()
{
  for (ListNode<T>* p=first; p; p=p->next)
    cout << p->data << " -> ";
  cout << "*\n";
}