How to write Template class copy constructor

Question

How to write copy constructor for a template class. So that if the template parameter is another user defined class it's copy constructor is also get called.

Following is my class

template <typename _TyV>
class Vertex {
public:
    Vertex(_TyV in) :   m_Label(in){ }
    ~Vertex() { }
    bool operator < ( const Vertex & right) const {
        return m_Label < right.m_Label;
    }

    bool operator == ( const Vertex & right ) const {
        return m_Label == right.m_Label;
    }

    friend std::ostream& operator << (std::ostream& os, const Vertex& vertex) {
        return os << vertex.m_Label;    
    }

    _TyV getLabel() { return m_Label;}
private:
    _TyV m_Label;
public:
    VertexColor m_Color;
protected:
};

Answer 1

Either a) not at all, just rely on the compiler-provided default; or b) by just invoking the copy constructor of the member:

template <typename T> struct Foo
{
  T var;
  Foo(const Foo & rhs) : var(rhs.var) { }
};

The point is of course that the compiler-provided default copy constructor does precisely the same thing: it invokes the copy constructor of each member one by one. So for a class that's composed of clever member objects, the default copy constructor should be the best possible.