Structural Design Patterns in Modern C++ - Using Composition Instead of Inheritance

The video tutorial discusses the challenges of using multiple inheritance in C, particularly the issue of class explosion when combining features like buffering, encryption, and compression. It introduces the decorator pattern as a more flexible solution, allowing for runtime feature addition and removal without modifying existing components. The tutorial then demonstrates how to implement composition over inheritance, using a compressed stream as an example, and concludes with code changes to illustrate the concept.

What problem arises when using multiple class inheritance in C for stream classes?

• It eliminates the need for virtual inheritance.

• It simplifies the class hierarchy.

• It causes the file to be opened twice.

• It leads to a single instance of the base class.

Why is the current design of stream classes not suitable for adding new features?

• It supports only single inheritance.

• It requires modifying existing classes.

• It is compatible with all programming languages.

• It leads to a large number of classes.

How does the decorator pattern improve the design of stream classes?

• By removing the need for inheritance.

• By making the design language-specific.

• By adding features at runtime.

• By simplifying the class structure.

What is the main advantage of composing classes instead of inheriting them?

• It allows for multiple instances of the base class.

• It enables runtime flexibility in adding features.

• It simplifies the use of virtual functions.

• It reduces the need for constructors.

In the decorator pattern, how is the functionality of the base class utilized?

• By duplicating it.

• By calling the base implementation.

• By ignoring it.

• By completely replacing it.

What change is made to the compressed stream class in the decorator pattern?

• It adds virtual inheritance.

• It removes all constructors.

• It uses a pointer to the file output stream.

• It inherits from multiple classes.

Why is it important to maintain the 'is-a' relationship in class design?

• To simplify the class hierarchy.

• To preserve the benefits of inheritance.

• To allow for flexible runtime behavior.

• To ensure compatibility with all programming languages.