Class template problem

[MatthewRock]

Hey, I am trying to learn how templates work(and how can I make use of them).
I want to make class Coordinates, that allows me to create coordinates of various types(so coordinates x and y can be int, double, or even of my own type, let's say, fraction).
However, I have problem with creating functions and making them work. Here's code:

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

int main()
{
    Coordinates<int> coor(3,12);
    coor.print();
    return 0;
}
//end of main.cpp

//Coordinates.h

#ifndef COORDINATES_H
#define COORDINATES_H
#include <iostream>

template <class T> class Coordinates{
    public:
        Coordinates() {};
        Coordinates(T ax, T ay) {x = ax; y = ay;}
        ~Coordinates() {};
        T getX() { return x; }
        void setX(T val) { x = val; }
        T getY() { return y; }
        void setY(T val) { y = val; }
        void print();
    protected:
    private:
        T x;
        T y;
};

#endif // COORDINATES_H
//end of coordinates.h

//coordinates.cpp

#include "Coordinates.h"
template <class T>
void Coordinates<T>::print() {
    std::cout<<"x: "<<x<<"\ny: "<<y<<std::endl;
}
//end of coordinates.cpp 

What compiler said:

main.cpp|7|undefined reference to `Coordinates<int>::print()'
I'm not sure if I understand the problem, and I definitely don't know how to fix it.

Also, I'd like to ask a bonus question, so I don't spam forum with other threads: when exactly should I create destructors? Only if my class have pointer? Or only if memory for this pointer is dynamically allocated?

[Peter87]

Templates is a bit special so you should implement the print() function in the header file to make it work.

Destructors are useful to clean up resources when the object is destructed. It could be freeing allocated memory, closing files, etc. In this case it looks unnecessary to declare a destructor because you don't do anything in it.