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

What is the primary purpose of the constructor in C++?

1. Memory allocation

2. Ensure variables are always initialized

3. To finalize an object

4. To overload functions

The correct answer is: Ensure variables are always initialized

A constructor in C++ is a special function that is responsible for initializing the object's data members and ensuring that the object is in a valid state. This means that the constructor is used to set up the initial values of the object's variables. Therefore, the primary purpose of a constructor is to ensure that the variables of an object are always initialized. Memory allocation is not the primary purpose of a constructor as it is handled by other functions in the program. Similarly, finalizing an object or overloading functions are not the primary purpose of the constructor. While these may be possible uses of the constructor, they do not accurately describe its primary purpose.