Creational Design Patterns in Modern C++ - Lazy Instantiation

The video tutorial explains the concept of singleton instances, focusing on eager and lazy instance creation. It highlights the differences between the two, with eager instances being created at program load and lazy instances only upon method call. The tutorial provides a step-by-step guide to implementing a lazy instance, including necessary code changes and null checks. It also addresses issues with the lazy instance, particularly the lack of destructor invocation, and suggests that solutions will be covered in the next lecture.

What is a key characteristic of an eager instance in the Singleton pattern?

• It is created as soon as the program loads.

• It is created when the user requests it.

• It is created only when needed.

• It is created after the main function is invoked.

In the lazy instance approach, when is the Singleton instance created?

• At the start of the program.

• When the instance method is called.

• After the main function ends.

• During the program compilation.

What is a potential issue with the lazy instance implementation?

• The instance is deleted prematurely.

• The instance cannot be accessed.

• The destructor is never invoked.

• The instance is created too early.

Why is it a bad idea to call delete on a non-pointer in the lazy instance implementation?

• It can cause the program to run slower.

• It can lead to undefined behavior.

• It can result in a segmentation fault.

• It can cause memory leaks.

What is a reason for not deleting the instance at the end of the main function?

• The instance is automatically deleted by the compiler.

• The instance is not accessible at that point.

• The instance might be needed for future programs.

• The instance might be used in destructors of global objects.