Question 1

After you have identified a set of classes needed for a program, you should now ____.

Accepted Answer

D  After identifying the classes, you should define their behavior (methods) and establish relationships (inheritance, associations) to ensure they interact correctly.

Question 2

Why is it generally considered good practice to minimize coupling between classes?

Accepted Answer

High coupling can lead to increased program maintenance as changes in one class may require changes in multiple other classes. It can also make it more difficult to reuse code in other parts of a program or in future projects. By minimizing coupling, classes can be designed to have clear responsibilities and interfaces, making them more modular and easier to maintain and reuse.

Question 3

You are designing an application to support an automobile rental agency.Which of the following probably should NOT be represented as an object?

Accepted Answer

Payment amount is not an entity that has behaviors or properties that can be encapsulated into an object. It is a value that can be stored as a data attribute or variable. The other choices, Automobile, Customer, and Rental contract, are all entities with properties and unique behaviors that can be encapsulated into objects.

Question 4

A class (ClassOne) is considered to have a dependency on another class (ClassTwo) under which of the following conditions?

Accepted Answer

ClassOne has a dependency on ClassTwo when it uses objects of ClassTwo. This means that ClassOne relies on the functionality provided by ClassTwo, and any changes made to ClassTwo may potentially impact the behavior of ClassOne.

Question 5

If many classes of a program depend on each other, we say that ____.

Accepted Answer

When many classes of a program depend on each other, it indicates that there is high coupling between the classes. Coupling refers to the degree of interdependence between modules or classes in a program. High coupling can lead to decreased maintainability and flexibility, making the program harder to change and update. Therefore, it is generally desirable to minimize coupling between classes.

Question 6

Classes often correspond to ____ in a requirements description.

Accepted Answer

Classes in object-oriented programming correspond to nouns in a requirements description. Nouns are typically used to represent entities or objects in the problem domain, which can then be modeled as classes in the software solution. Verbs, dependencies, and relationships may also appear in requirements descriptions, but they do not directly correspond to classes in the same way that nouns do.

Question 7

In a UML diagram, dependency is denoted by ____.

Accepted Answer

Dependency is denoted by a dotted/dashed line with an open arrow tip in UML diagrams. This indicates that one class, called the independent class, uses or depends on another class, called the dependent class.

Question 8

Which of the following would be an appropriate name for a class used in an inventory application?

Accepted Answer

A class named "Product" would be appropriate for an inventory application as it represents a single item being tracked in the inventory system. The other options relate to specific actions or functions that could be part of the application but do not represent the overarching object being managed.

Question 9

A UML class diagram would be most useful in visually illustrating which of the following?

Accepted Answer

Dependencies between classes are best represented visually using a UML class diagram.

Question 10

What is a general naming convention for a class?

Accepted Answer

Generally, class names should be descriptive nouns. This helps to accurately convey the purpose and behavior of the class to other developers who may use it in their code.

Question 11

A/an ____ is used to create objects with the same behavior.

Accepted Answer

A class is used to create objects with the same behavior. Classes define the properties and methods shared by all instances of the class, allowing for consistent and maintainable code. Associations, aggregations, and dependencies are all different types of relationships between classes or objects, but do not define the behavior of the objects themselves.

Question 12

When using the CRC method, other classes that are needed to fulfill the responsibilities of a given class are called its ____.

Accepted Answer

When using the CRC method, the other classes that are needed to fulfill the responsibilities of a given class are called collaborators. These classes work together with the given class to achieve a common goal. The CRC method is a collaborative approach to design and development, and recognizing the necessary collaborators for each class is a fundamental aspect of this methodology. Related classes or responsible classes do not fully capture the notion of collaboration in this context, while concurrent classes may or may not be collaborators depending on the specific design.

Question 13

Dependency between classes denotes that ____.

Accepted Answer

Dependency between classes means that objects in one class use objects in another class to perform their functions. This dependency can be through method calls or parameter passing. Therefore, option D is the correct choice as it refers to the use of objects of another class by methods in objects of one class.

Question 14

A CRC card describes ____.

Accepted Answer

A CRC card is a tool used in object-oriented programming to describe a class, its responsibilities, and its collaborators. The card typically includes the class name, its attributes and methods, and a list of other classes it communicates with or depends on. This helps developers to better understand the structure and interactions of their code.

Question 15

Which of the following questions should you ask yourself in order to determine if you have named your class properly?

Accepted Answer

A class name should be a noun or noun phrase that describes the objects it represents, not a verb or task description.

Question 16

How many responsibilities is/are recommended by researchers on a CRC card?

Accepted Answer

Researchers recommend at most three responsibilities per CRC card to keep the design simple and manageable.

Question 17

When you begin designing a program, you work from a ____, a description of what your program should do.

Accepted Answer

A requirements specification is a detailed document outlining the specific requirements that a program must meet in order to be successful. It is one of the first steps in the software development life cycle and serves as a guide for the development team throughout the process. It includes information such as the goals of the program, user needs, system specifications, and functional requirements.

Question 18

Which of the following most likely indicates that you have chosen a good name for your class?

Accepted Answer

If the name of the class clearly indicates what object it represents, it is a good indication that the name is appropriate and understandable. This helps other programmers understand the purpose of the class and how to use it in their own code. The other options may not necessarily indicate a good name for a class.

Question 19

When using the CRC method, if you determine that a class cannot carry out a particular task by itself and needs the help of another class to complete the task, you should ____.

Accepted Answer

In the CRC (Class-Responsibility-Collaborator) method, if a class cannot complete a task by itself and requires the assistance of another class, you should add the assisting class onto the original class's CRC card as a collaborator. This indicates the dependency and collaboration needed to fulfill the responsibilities.

Question 20

Which of the following is the most important consideration when designing a class?

Accepted Answer

The most important consideration when designing a class is to ensure that it represents a single concept or object from the problem domain. This helps to make the code more understandable, maintainable, and flexible. Option A is incorrect because not all classes need to represent a mathematical concept. Option C is arbitrary and not based on any best practices. Option D is partially correct but may not always be true as there may be cases where multiple closely related concepts may need to be represented in a single class.

Quiz 12: Object-Oriented Design