5. In what ways can aggregation be distinguished from composition for a whole-part relationship?
Aggregation and composition are both forms of the whole-part relationship in object-oriented programming, but there are some key differences that distinguish them from each other:
1. Ownership: In composition, the whole object owns the part objects, meaning that the part objects cannot exist without the whole object. In aggregation, the part objects are not owned by the whole object, and can exist independently.
2. Lifecycle: In composition, the part objects are created and destroyed along with the whole object. In aggregation, the part objects can exist before and after the whole object.
3. Relationship Multiplicity: In composition, there is typically a one-to-one or one-to-many relationship between the whole and its parts. In aggregation, there can be a many-to-many relationship between the whole and its parts.
4. Navigation: In composition, the part objects are usually accessed through the whole object. In aggregation, the part objects can be accessed directly.
5. Flexibility: Aggregation is more flexible than composition, as it allows for a looser relationship between the whole and its parts. Composition creates a stronger and more dependent relationship between the whole and its parts.