What happens when you attempt to compile and run the following code?

#include

using namespace std;

template

class A {

T_v;

public:

A() {}

A(T v): _v(v){}

friend ostream & operator<<(ostream & c, const A & v);

};

template

ostream & operator<<(ostream & c, const A & v) {

c<

int main()

{

Aa(10);

cout<<a<

return 0;

}