call to pure virtual function from base class constructor

There are many articles that explain why you should never call virtual functions in constructor and destructor in C++. Take a look here and here for details what happens behind the scene during such calls.

In short, objects are constructed from the base up to the derived. So when you try to call a virtual function from the base class constructor, overriding from derived classes hasn't yet happened because the derived constructors haven't been called yet.

Trying to call a pure abstract method from a derived while that object is still being constructed is unsafe. It's like trying to fill gas into a car but that car is still on the assembly line and the gas tank hasn't been put in yet.

The closest you can get to doing something like that is to fully construct your object first and then calling the method after:

template <typename T>
T construct_and_print()
{
  T obj;
  obj.PrintStartMessage();

  return obj;
}

int main()
{
    Derived derived = construct_and_print<Derived>();
}