C++ Error : undefined reference to `Vector2<int>::add(int)'

Question

I'm new to C++

I have been attempting to write a linked list below you can see I have linkedList header and implement and a main file I'm using MinGW-W64 as compiler

in my linkedList.h I have template struct Node and a template class Vector2

// linkedList.h
template <class T>
struct Node
{
    T value;
    Node *next;
};

template <class T>
class Vector2
{
private:
    Node<T> root;

public:
    void add(T value);
    ~Vector2();
};

in my linkedList.cpp I implemented void Vector2<T>::add(T value); and Vector2<T>::~Vector2();

// linkedList.cpp
#include <iostream>
#include "linkedList.h"

using namespace std;

template <class T>
void Vector2<T>::add(T value)
{
    Node<T> *newNode = new Node<T>;
    newNode->value = value;

    if (root == nullptr)
    {
        newNode->value = nullptr;
        root = newNode;
        return;
    }

    newNode->next = root;
    root = newNode;
}

template <class T>
Vector2<T>::~Vector2()
{
}

in main I created a Vector2 vec;

// main.cpp
#include <iostream>
#include "linkedList.h"

using namespace std;

int main()
{
    Vector2<int> vec;
    vec.add(12);
    return 0;
}

when I compile my code I get this errors

$> make
g++ -g -Wall -o build\main main.cpp linkedList.cpp && echo Executing build\main && build\main.exe
\AppData\Local\Temp\ccb8gQgf.o: In function `main':
\Desktop\github\c\templates/main.cpp:9: undefined reference to `Vector2<int>::add(int)'
\Desktop\github\c\templates/main.cpp:10: undefined reference to `Vector2<int>::add(int)'
\Desktop\github\c\templates/main.cpp:11: undefined reference to `Vector2<int>::add(int)'
\Desktop\github\c\templates/main.cpp:8: undefined reference to `Vector2<int>::~Vector2()'
\Desktop\github\c\templates/main.cpp:8: undefined reference to `Vector2<int>::~Vector2()'
collect2.exe: error: ld returned 1 exit status
make: *** [makefile:13: main] Error 1

Answer 1

Template functions cannot be diveded as multiple files. You must inplement it in your header file.