模板类的友元重载函数

#include

using namespace std;

template

class Test 

{

public:

friend ostream& operator << <> (ostream& out, const Test& obj);

Test(T n=0):num(n){}

Test(const Test& copy)

{

num = copy.num;

}

private:

T num;

};

template

ostream& operator << <> (ostream& out, const Test& obj)

{

out<

return out;

}

int main()

{

Test t(2);

cout<

return 0;

}

或者是

#include

using namespace std;

template

class Test 

{

public:

 template

friend ostream& operator << (ostream& out, const Test& obj);

Test(T n=0):num(n){}

Test(const Test& copy)

{

num = copy.num;

}

private:

T num;

};

template

ostream& operator << (ostream& out, const Test& obj)

{

out<

return out;

}

int main()

{

Test t(2);

cout<

return 0;

}