c++ - how to query if(T==int) with template class

Question

When I'm writing a function in a template class how can I find out what my T is?

e.g.

template <typename T>
ostream& operator << (ostream &out,Vector<T>& vec)
{
if (typename T == int)
}

How can I write the above if statement so it works?

Answer 1

Something like this:

template< class T >
struct TypeIsInt
{
    static const bool value = false;
};

template<>
struct TypeIsInt< int >
{
    static const bool value = true;
};

template <typename T>
ostream& operator << (ostream &out,Vector<T>& vec)
{
    if (TypeIsInt< T >::value)
    // ...
}