Mastering C++: A Comprehensive Quiz Based on 'Thinking in C++'

How is upcasting within an array of base class pointers demonstrated in the example?

1. By manually casting each derived object to a base class type

2. Through a polymorphic function call

3. By initializing the array with new derived objects

4. All of the above

The correct answer is: By initializing the array with new derived objects

Upcasting within an array of base class pointers is demonstrated by initializing the array with new derived objects. This is because upcasting involves converting a derived class object to a base class object, and by initializing the array with new derived objects, the objects will automatically be upcasted to base class objects. Option A is incorrect because manually casting each derived object to a base class type is not the most efficient way to demonstrate upcasting in an array. Option B is incorrect because polymorphic function calls do not necessarily involve upcasting, as they can also involve dynamic binding. Option D is incorrect because although all of the options may demonstrate upcasting in some way, only option C accurately describes the scenario given in the question.