What does the constructor function do in a C++ class?

The constructor function plays a crucial role in C++ classes by initializing an object when it is created. When a new instance of a class is instantiated, the constructor is automatically called to set up the initial state of the object. This process often includes allocating memory for the object's attributes and setting them to specific values, which may be default or provided through parameters.

Using a constructor allows for safe and organized object creation, as it ensures that an object is in a valid state before it is used in the program. This initialization step is vital because it prevents issues that can arise from unassigned or improperly assigned member values. Constructors can also take parameters, allowing for flexibility and customization during object initialization.

While setting default values for an object's attributes is indeed part of what a constructor might do, the primary function of constructors is to facilitate the full process of object initialization. Other options described do not accurately characterize the purpose of a constructor; for instance, one of them suggests that it executes at the end of a program, which is not the case. Overall, the constructor embodies the concept of object-oriented programming by managing how instances of classes are created and initialized.