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)     // ... } 

Answer 2

Since C++11 we have std::is_same:

if (std::is_same<T, int>::value) ... 

It's implemented similar to the suggested trait TypeIsInt suggested in the other answers, but with two types to be compared.