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

The video tutorial introduces the visitor design pattern, using a shape hierarchy as an example. It explains the need for the pattern to add operations like calculating perimeter or area without modifying existing classes, adhering to the open-closed principle. The tutorial outlines the implementation of a shape hierarchy, including classes for line and circle geometries, and discusses the addition of operations without the visitor pattern. The video concludes with a plan to introduce a hierarchy of visitors to represent new operations.

Why is the visitor design pattern suitable for adding operations to a shape hierarchy?

• It allows adding operations without modifying existing classes.

• It automatically calculates the perimeter and area.

• It simplifies the code by merging all classes into one.

• It eliminates the need for any class hierarchy.

What is the primary role of the base class Shape in the shape hierarchy?

• To store common behavior for all shapes.

• To render shapes on the screen.

• To act as a placeholder for virtual destructors.

• To calculate the area of all shapes.

Which attributes are necessary for defining the basic geometry of a line?

• Height and base

• Radius and diameter

• Starting point and ending point

• Length and width

What is the main reason for not adding common behavior in the base class of the shape hierarchy?

• All shapes have identical geometry.

• Different shapes have different geometry.

• The base class is meant for rendering only.

• The base class is used for storing data.

What additional attribute is needed for the circle class besides its position?

• Diameter

• Circumference

• Radius

• Area