Defining method with additional template parameters out of line

Given a templated class, how do I define a (further templated) method out of line? The syntax

template<class T> class C {
    public:
    template<class S> void f();
};

template<class S, class T> void C<T>::f<S>(){}

or any variant I have tried does not do the job:

error: use 'template' keyword to treat 'f' as a dependent template name
template<class S, class T> void C<T>::f<S>(){
                                      ^
                                      template
error: nested name specifier 'C<T>::' for declaration does not refer into a class, class template or class template partial specialization

>Solution :

You need to write two template headers:

template<class T>
template<class S>
void C<T>::f(){}