C ++ Template Class Type Errors

Question

I am working on a class of linked list templates to do the same with various variables, and have managed to deal with most problems. Unless I am compiling, I get the following data:

g++ -Wall -o template_test template_test.cpp In file included from template_test.cpp:1:0: LinkedList.h:50:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:51:30: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:56:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:57:51: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:92:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:93:31: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:102:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:103:34: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:119:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:120:48: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:158:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:159:37: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:193:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:194:34: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' LinkedList.h:210:11: error: declaration of 'class Type' LinkedList.h:7:11: error: shadows template parm 'class Type' LinkedList.h:211:34: error: invalid use of incomplete type 'class LinkedList<Type>' LinkedList.h:8:7: error: declaration of 'class LinkedList<Type>' make: *** [template_test] Error 1 

Pretty much it says the same for every template function that I have. Can someone decrypt for me what these messages mean, what makes the compiler throw these messages, and how can I fix it? I will be re-reading and possibly re-writing my code in the meantime.
My code is as follows:

 #include <string> #include <iostream> using namespace std; template <class Type> class LinkedList{ public: * default constructor and a copy constructor that creates a copy * of the given object*/ LinkedList(); //default construtor LinkedList(const LinkedList& lst); //copy constructor ~LinkedList();//destructor void add(Type data); void insertAt(int pos, Type data); bool remove(Type data ); void removeAll(); void printList(); template <class Type> LinkedList<Type>::LinkedList(){ head = NULL; size = 0; //Don't forget to do this!!! } template <class Type> LinkedList<Type>::LinkedList(const LinkedList& lst){ if (lst.head == NULL){ head = NULL; size = 0; } else{ head = new Node; head->data = lst.head->data; Node *pNewNode = head; Node *pOldNode = lst.head->next; while (pOldNode != NULL){ pNewNode->next = new Node; pNewNode = pNewNode->next; pNewNode->data = pOldNode->data;; pOldNode = pOldNode->next; } pNewNode->next = NULL; size = lst.size; } } template <class Type> LinkedList<Type>::~LinkedList(){ removeAll(); } template <class Type> void LinkedList<Type>::add(Type x){ Node *p = new Node; //temporary node // Assign appropriate values to the new node p -> data = x; p -> next = head; // Make the head point to the new node head = p; size++; } template <class Type> void LinkedList<Type>::insertAt(int pos, Type x){ Node *p; Node *newNode; // Check that pos is a valid index if (pos <= size){ newNode = new Node; //new node newNode->data = x; // Deal with case when item is to be inserted at the head of the list if (pos == 0){ newNode->next = head; head = newNode; }// if(pos == 0) else{ p = head; // Move to position BEFORE insertion point for(int i = 0; i < pos-1; i++){ // Check that p points to a node // Note using exception handling should throw an exception if(p == NULL){ return; } p = p->next; }//for // Insert node newNode->next = p->next; p->next = newNode; }//else (pos != 0) size++; }//else (pos >= size) do nothing } template <class Type> bool LinkedList<Type>::remove(Type x){ Node *p = head; Node *temp; if (head == NULL){ return false; } else if (head->data == x){ head = head->next; delete p; //currently assigned head size--; return true; } else{ while(p->next != NULL){ // Check next node for target if(p->next->data == x){ temp = p->next; p->next = p->next->next; delete temp; return true; } p = p->next; } } return false; } template <class Type> void LinkedList<Type>::removeAll(){ Node *p = head; // Traverse the list deleting nodes while (p!= NULL){ head = head->next; // Mustn't "lose" the next node delete p; // De-allocate memory p = head; // Go to next node } head = NULL; size = 0; } template <class Type> void LinkedList<Type>::printList(){ Node *p = head; cout << "["; //Nice format! // Traverse the list while (p != NULL){ cout << p -> data; // Print data p = p -> next; // Go to next node if (p != NULL){ cout << ","; // Print a comma unless at the end of the list } } cout << "]"; // Don't print a newline - it might not be wanted } private: struct Node { Type data; //list data Node *next; //pointer to next item in the list }; Node *head; //Pointer to the first node in the list int size; //Records the number of nodes in the list }; 

Answer 1

The syntax is used to define a member function outside the class of a class within a class. This does not work.

This should do it:

 template<typename X> class Foo { public: void f(); }; // notice end of class scope here template<typename X> void Foo<X>::f() { // impl }