Tests if type has trivial default constructor.
template<class Ty>
    struct has_trivial_default_constructor;
Parameters
- Ty
 The type to query.
Remarks
An instance of the type predicate holds true if the type Ty is a class that has a trivial constructor, otherwise it holds false.
A default constructor for a class Ty is trivial if:
- it is an implicitly declared default constructor 
- the class Ty has no virtual functions 
- the class Ty has no virtual bases 
- all the direct bases of the class Ty have trivial constructors 
- the classes of all the non-static data members of class type have trivial constructors 
- the classes of all the non-static data members of type array of class have trivial constructors 
Requirements
Header: <type_traits>
Namespace: std