Class template issue ver2

661193

You may not have created an object

such as

         One<10,20> o1;
fun2(o1);
cout<<o1<<endl;

Two<int> ti1;
cout<<ti1<<endl;
fun1(ti1);

661193

Although my question may not have any practical value, if this question is not understood

I really can't learn anymore, there is always a pimple in my heart

I hope that a master who sees through C++ will come to pull the rookie!

puniaball

The most direct way is to throw the declaration and definition of the non-binding friend template function in the class body

661193

New discovery in vs

Two's output overload function can be compiled

It seems this question is really dark, ha ha

superandy

template<int i1,int i2>
class One
{
template<int ii1,int ii2> friend ostream&operator<<(ostream&,const One<ii1,ii2>&);
template<int ii1,int ii2> friend void fun2(const One<ii1,ii2>&);
};

template<int ii1,int ii2> ostream&operator<<(ostream&x,const One<ii1,ii2>&){return x;}
template<int ii1,int ii2> void fun2(const One<ii1,ii2>&){}

template<class T>
class Two
{
template<class TT> friend ostream&operator<<(ostream&,const Two<TT>&);
template<class TT> friend void fun1(const Two<TT>&);

};

template<class TT> ostream&operator<<(ostream&x,const Two<TT>&){return x;}
template<class TT> void fun1(const Two<TT>&){}