Class template problem

661193

template <class Type>
class Bar
{
   template <class T> friend void Foo1 (const T&);
};

How can Foo1 be defined outside the template class Bar?

I wrote it like this
template <class T> void Foo1 (const T&) {}

But when compiling, it says error C2668: "Foo1": The call to overloaded function is ambiguous
May be the one declared in the template class, or the one defined outside

What should I do?

orangedj

template<class T>
void Bar<T>::Foo1(const T&)
{}

661193

Is it wrong on the second floor?

Foo1 is not a member function

orangedj

template<class T>
class Bar
{
   template<class T2>
   friend void Foo1(const T2&);
};

template <class T2>
void Foo1(const T2&)
{}

//Look at the member template

orangedj

Wrong, I can compile this

orangedj

#include <iostream>

template<class T>
class Bar
{
public:
   Bar(T b): b_(b) {}
   
   template<class T2>
   friend void Foo1(const T2&);
private:
T b_;
};

template <class T2>
void Foo1(const T2&t)
{
std::cout << t.b_ << std::endl;
}

int main()
{
Bar<int> b(5);
The
Foo1(b);
The
return 0;
}

冷夜星光

The program upstairs cannot be compiled in vc! There are two errors? ? ? ...
error C2668:'Foo1': ambiguous call to overloaded function

orangedj

I use MinGW

c3x2z1

Can be compiled by A