C++ template question

Hello all, I am new to using templates and run into a problem:

I have a file foo.h:

#ifndef FOO_H_
#define FOO_H_

class foo{
public:
foo();
template <unsigned int ID>
int doSomething();
virtual ~foo();
};

#endif /* FOO_H_ */

and a foo.cpp:

#include "foo.h"

foo::foo() {
}

template <unsigned int ID>
int foo::doSomething(){
....
}

foo::~foo() {
}

and in my main.cpp I want to do something like:

#include "foo.h"

int main(int argc, char *argv[]){
foo *bar = new foo();
foo->doSomething<2u>();
return 0;
}

The problem is that whenever i try this i get undefined reference to `int foo::doSomething<2u>()

I have tried a number of variations to call the template (and tbh I am not even sure what I want to is possible) but no success.

Any Help would be greatly appreciated. Thank you.

I meant to write:

#include "foo.h"

int main(int argc, char *argv[]){
foo *bar = new foo();
bar->doSomething<2u>();
return 0;
}

typo and problem still exists.

The simplest solution is to move the function body dosomething into the header file so the compiler sees it when it instantiates the code for the template.

...that applies to all functions of the template class.