Question

The has-a relation between classes is best implemented using the mechanism of class _________.

Short answer

Answer: Class composition.

Step-by-step solution

Understand the statement

In the given statement, we are looking for a mechanism that allows us to implement the has-a relationship between classes.

Review inheritance, composition, and aggregation

There are three common ways of establishing relationships between classes: 1. Inheritance: Represents an is-a relationship, where a subclass (derived class) inherits properties and methods from a superclass (base class). 2. Composition: Represents a strong has-a relationship, where the containing class is responsible for the existence and lifetime of the contained class. 3. Aggregation: Represents a weak has-a relationship, where the containing class is not responsible for the existence and lifetime of the contained class.

Choose the best mechanism for implementing the has-a relationship

Based on the definitions of inheritance, composition, and aggregation, we can conclude that both composition and aggregation represent a has-a relationship. However, the statement asks for the "best" method to implement the relationship. Since composition represents a strong has-a relationship and provides better encapsulation, it is considered the best mechanism for implementing the has-a relationship between classes.

Complete the statement

Based on our analysis, composition is the best method for implementing the has-a relationship. So the completed statement should be: "The has-a relation between classes is best implemented using the mechanism of class composition."