What is the primary purpose of a destructor in a class?

The primary purpose of a destructor in a class is to clean up resources when an object is destroyed. In C++, when an object is no longer needed and goes out of scope or is explicitly deleted, the destructor is automatically called. This special member function allows developers to release resources that the object may have acquired during its lifetime, such as dynamic memory, file handles, or network connections. By properly implementing a destructor, you help prevent memory leaks or resource contention problems that can arise when an object is no longer in use but its resources are not released.

Destructors are typically used to ensure that any dynamically allocated memory is freed, maintaining efficient use of memory and resources within the application. This cleanup process is crucial for resource management in C++ as it empowers the language's low-level control over memory and enhances the robustness of the application.

The other options pertain to different functionalities in class management: creating instances relate to constructors; initializing data members pertains to constructors as well; and defining behaviors of an object typically refers to member functions. All of these are important aspects of class design but do not reflect the specific role of a destructor.