How to get the default value of any type

Question

In C# I can write something like this:

    class AnyThing
    {
        static public T Default = default(T);
    }

    static void Main ()
    {
              


        

Answer 1

Create your own default keyword:

class default_t
{
public:
  template
  operator T() const { return T(); }
};

default_t const default = default_t();

Use it like:

int myInt = default;
vector myVector = default;
shared_ptr myPtr = default;

Or with a slight semantic variation:

default_t const empty = default_t();

vector fetchPersons()
{
  if (Database::isConnected())
  {
    return Database::fetchPersons();
  }

  return empty;
}