Mixing virtual and non-virtual inheritance of a base class

Question

This is the code:

struct Biology
{    
    Biology() { cout << \"Biology CTOR\" << endl; }
};

struct Human : Biology
{    
    Human() { cout &l         


        

Answer 1

Non virtual inheritance is an exclusive relationship, like membership. A class can be the non-virtual base class of one other class in a given complete object.

This implies that a class can override virtual functions of a non virtual base class without causing conflicts or issues.

A constructor can also initialize non virtual bases reliably.

Only virtual bases can be direct base classes of many indirect bases of a complete object. Because a virtual base class can be shared, overriders can conflict.

A constructor can try to initialize a virtual base subobject in the ctor-init-list, but if the class is further derived, that part of the ctor-init-list will be ignored.