I do not know why my extern template is not working while I'm going to create a new object of my template class

Question

I have written down a code to show myself how I can use templates. My class is in an .h file and my classdefinition is in an .cpp file.

Following content is in the .h file:

template <class T>
class one
{
private:
  T data;

public:
  one();
  one(T s);
  T two();
  T getData(); 
};

Content of the .cpp file:

#include <iostream>

using namespace std;

#include "template.h"


template <class T>one<T>::one()
{
}

template <class T> one<T>::one(T s)
{
}

template <class T> T one<T>::two()
{
   return 0;
}

template <class T> T one<T>::getData()
{
  return 0;
}

with the following file I try to indicate the object of the class one:

int main()
{
  one<string> * s = new one<string>;
  return 0;
}

Now I got following compiler error:

/tmp/cchK1XpI.o: In function main': templatetest.cpp:(.text+0x1c): undefined reference toone::one()' collect2: error: ld returned 1 exit status

I tried to understand where the wrong reference is but cant find it. (I tried it aswell with type int and the same error showed. So if anyone have a solution for this please share it with me!