Behavioral Design Patterns in C++ - Shapes Example - II

The lecture discusses rendering shapes on a screen without modifying shape classes. It explores using dynamic casting to handle different shape attributes and methods. The instructor demonstrates drawing lines and circles using Win32 APIs, emphasizing the need for a window handle and device context. The render class is implemented to facilitate this process. Challenges with dynamic casting are highlighted, and the visitor design pattern is introduced as a solution for adding new operations without modifying existing classes.

What is one reason for not adding a draw function directly to the shape hierarchy?

• It makes the code more efficient.

• It adds unnecessary responsibilities to shape classes.

• It simplifies the shape classes.

• It allows for easier debugging.

Why is dynamic casting used when rendering shapes?

• To simplify the code structure.

• To improve the performance of the application.

• To determine the exact type of shape at runtime.

• To avoid using Win32 APIs.

What is required to draw shapes on the screen using the renderer class?

• The handle of the window.

• A static method called run.

• A list of shape names.

• A message loop.

Which API is used to draw a line in the application?

• OpenGL API

• DirectX API

• Vulkan API

• Win32 API

What must be implemented for the window to be displayed on the screen?

• A message loop

• A rendering engine

• A graphics card driver

• A shape hierarchy

What is a disadvantage of using runtime type identification?

• It simplifies the code.

• It improves application performance.

• It requires dynamic casting, which can affect performance.

• It eliminates the need for a message loop.

What design pattern is introduced to handle adding new operations?

• Observer Pattern

• Factory Pattern

• Singleton Pattern

• Visitor Pattern