Is it possible to make a template function friend of a class?

Question

C++ / C#

In general, I have a class. it has certain fields. one object of this class is a global variable. and so it turned out that two template functions need to access the fields of this object directly. I do not want to make fields public, encapsulation is violated. and only these two templates are accessed outside the class. is it possible to make template functions members of a class - I don’t know, and they shouldn’t be them logically

Answer 1

#include <iostream>

class Wrap
{
public:
    Wrap(int x) : value(x) {}
private:
    int value;

    template <class T>
    friend void out(const T&);
};

template <>
void out(const Wrap& x)
    { std::cout << x.value << std::endl; }

int main()
{
    Wrap x(42);
    out(x);
    return 0;
}

If needed in a namespace...

spoiler

#include <iostream>

namespace qq {
    template <class T>
    void out(const T&);
}

class Wrap
{
public:
    Wrap(int x) : value(x) {}
private:
    int value;

    template <class T>
    friend void qq::out(const T&);
};

template <>
void qq::out(const Wrap& x)
    { std::cout << x.value << std::endl; }

int main()
{
    Wrap x(42);
    qq::out(x);
    return 0;
}