Thread: Understanding Link List

Will someone help me out in building a link list with a tail and header pointers?
I did google, but i couldnt find anything useful.

Code:

struct Node
{
   Nutricalc Data;
   Node* next;
};




class FoodLists
{

public:

	// constructors
    FoodLists();
    FoodLists(char fileName[]);
    FoodLists(int initCapacity);

    FoodLists(const FoodLists& aList);


	// member functions
    void deletefood(int index);
    void addFood(const Nutricalc &aFood);
    void listFood();
    bool searchByName(char title[], Nutricalc& afood) const;
    bool searchByCategory(Category cat, FoodLists & food) const;
    int getSize()const;
    void writeOut(char fileName[]) const;
    
    // destructor
    ~FoodLists();

	
private:
	//data members
   Node * head;
   Node * tail;
   int size; 

/ void addAtBeginning(const Nutricalc& afood);
  void addAtEnd(const Nutricalc& afood);
//void addSorted(const Nutricalc& afood);

};

now if i want to build a list with my head and tail pointers i would do this?

head = tail;
tail->next = new Node; // or NULL?
tail = tail->next;

will that give me an empty list using the class FoodLists tail and head pointer?
any help is much appreciated!

Corey

I didn't get your question. Does the problem require using the FoodLists class? If you want to have an empty class, why do you allocate memory for the tail node? And what does it mean to use tail and head pointers of FoodLists class to create a linked list? FoodLists is already a linked list wrapper. Why don't you use public functions of the class to create a list then?

If you want to create a list involving two nodes, this is what you might want to do.

Node* pHead = NULL;
Node* pTail = NULL;
pHead = new Node();
pHead->next = new Node();
pTail = pHead->next;
pTail->next = NULL;

Sorry for the confusion. I want to use the head and tail pointer i have already created in the foodlists class. The reason why i said an empty list is i thought it would be easier to make for learning purposes. Now of course I will be filling it up with information, which i know how to do. I have some functions already made.