"unresolved external symbal" on template class

Question

I have worked on this same problem for three days, I can't do anything about it. Please Help!!

This is not a duplicate of a question with a similar name. The name is similar, but the problem is completely different.

May have something to do with External Dependencies is what I am told.

I am posting all of my code, and if I need to post more info please ask!

list_test.cpp This does more, but this is where it messes up.

 #include <cctype>       // Provides toupper
 #include <iostream>     // Provides cout and cin
 #include <cstdlib>      // Provides EXIT_SUCCESS
 #include "list.h"  // With value_type defined as double
 #include "Node.h"
 #include "Iterator.h"
 using namespace std;
 using namespace list_1;

 int main( )
 {
     list<double> test;
 }

iterator.h

 // Template CLASS PROVIDED: Iterator 

 #pragma once
 #include "Node.h"

 namespace list_1
 {
template<typename T>
class Iterator
{
    public:
    Iterator<T> (Node<T> *np);
    // precondition: is_item is true
    // post condition n points to the next item in the list
    void operator++();
    // precondition: 
    // postcondition: returns true if there is a valid item
    bool is_item();
    // precondition: is_item == true
    // postcondition returns data that n is pointing at
    T operator* ();

    private:
    Node<T>* n;

};

template<typename T>
Iterator<T>::Iterator (Node<T> *np)
{
    n = np;
}

template<typename T>
void Iterator<T>::operator++()
{
    assert(is_item( ) == true);

    n = n->next;
}

template<typename T>
bool Iterator<T>::is_item()
{
    return (n->data != NULL);
}

template<typename T>
T Iterator<T>::operator* ()
{
    assert(is_item( ) == true);

    return n->data;
}
 }

Node.h

 #pragma once

 namespace list_1
 {
template <typename T>
struct Node
{
    T data;
    Node<T> *next;

    // Constructor
    // Postcondition: 
    Node<T> (T d);
};

template <typename T>
Node<T>::Node(T d)
{
    data = d;
    next = NULL;
}
 }

list.h

 #include "Node.h"
 #include "Iterator.h"

 namespace list_1
 {
template <typename T>
class list
{
    public:
        // CONSTRUCTOR
        list();
        // postcondition: all nodes in the list are destroyed.
        ~list();
        // MODIFICATION MEMBER FUNCTIONS
        //postcondition: entry is added to the front of the list
        void insert_front(const T& entry);
        //postcondition: entry is added to the back of the list
        void add_back(const T& entry);
        // postcondition: all nodes with data == entry are removed from the list
        void remove_all(const T& entry);
        // postcondition: an iterator is created pointing to the head of the list
        Iterator<T> begin(void);
        // CONSTANT MEMBER FUNCTIONS
        // postcondition: the size of the list is returned
        int size( ) const;
    private:
        Node<T>* head;
};

template <typename T>
list<T>::list( )
{
    head = NULL;
}

template <typename T>
list<T>::~list()
{

}

template <typename T>
void list<T>::insert_front(const T& entry)
{
    // head = new node(entry, head);
}

template <typename T>
void list<T>::add_back(const T& entry)
{

}

template <typename T>
void list<T>::remove_all(const T& entry)
{

}

template <typename T>
Iterator<T> list<T>::begin(void)
{
    //Iterator<T> traverse( );
    //return traverse;
}

template <typename T>
int list<T>::size( ) const
{
    int size = 0;
    Node<T> *tempPoint = head;

    for (tempPoint = head; tempPoint != NULL; tempPoint = tempPoint->next)
    {
        size ++;
    }

    return size;
}
 }

Here is the error message:

 1>------ Build started: Project: CS2420LinkedList, Configuration: Debug Win32 ------
 1>list_test.obj : error LNK2019: unresolved external symbol "public: __thiscall list_1::list<double>::~list<double>(void)" (??1?$list@N@list_1@@QAE@XZ) referenced in function _main
 1>list_test.obj : error LNK2019: unresolved external symbol "public: __thiscall list_1::list<double>::list<double>(void)" (??0?$list@N@list_1@@QAE@XZ) referenced in function _main
 1>C:\Users\KyleYas\Documents\Visual Studio 2010\Projects\CS2420LinkedList\Debug\CS2420LinkedList.exe : fatal error LNK1120: 2 unresolved externals
 ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

Thank you for the answers! I found the problem. I had two of the same list.h files in the External Dependencies, so I just deleted it and it compiled. I don't know how it happened, I guess I set up my program incorrectly.

Answer 2

I wouldn't necessarily defend its use but I don't think your problem is the using statement. I can't see any reason to have collision when you don't #include <list>. That would be:
error C2872: 'list' : ambiguous symbol....

From what the message says I would start by making sure that list.h is where it's supposed to be.

Also, you can always reference VS error codes like the LNK2019 you're getting and check the examples against your issues.