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Basic Object Oriented Programming (OOP) MCQ

1. What are the four principles of object-oriented programming?

Answer

Correct Answer: Abstraction, encapsulation, inheritance, and polymorphism

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2. What parameters are required to be passed to a class constructor?Here they haven't mentioned any specific language so let's consider all languages.

Answer

Correct Answer: None // Above 3 are incorrect so

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3. What is the difference between an interface and an abstract class?

Answer

Correct Answer: Abstract classes can contain code or data. Interface do not contain code or data. A class can inherit from only one abstract class but can implement an unlimited number of interfaces

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4. What is the difference between early binding and late binding?

Answer

Correct Answer: Early binding is when a variable is assigned its value at compile time. Late binding is when a variable is assigned a value at run time

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5. How does dynamic typing complicate troubleshooting?

Answer

Correct Answer: It can be difficult to identify variables that are incorrectly typed

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6. What does a concrete class not have?

Answer

Correct Answer: Pure virtual functions

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7. Static polymorphism uses method _ ?

Answer

Correct Answer: Overloading

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8. In the context of OOP, what is composition?

Answer

Correct Answer: Composition is a part/hole relationship where an object is composed of one or more other objects, each of which is considered a part of the whole.

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9. An instance of which type of class cannot be created?

Answer

Correct Answer: Abstract class

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10. What is the function of a finalizer or destructor?

Answer

Correct Answer: To relinquish resources that are no longer needed

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11. Which choice is not an OOP language?

Answer

Correct Answer: C

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12. What is the purpose of the finally block?

Answer

Correct Answer: To always run the finally block of code when the try block exits

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13. What is the main idea behind separation of concerns?

Answer

Correct Answer: All of these answers

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14. Assume single inheritance is used with classes A and B while A is the base class. Then assume classes C, D, and E, where C is a base class and D is derived from C, then E is derived from D. Class C is made to inherit from class B. Which type of inheritance is reflected?

Answer

Correct Answer: Multilevel

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15. Methods and attributes that define an object are a kind of blueprint called what?

Answer

Correct Answer: A class

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16. What is the scope of a class nested inside another class?

Answer

Correct Answer: Global scope

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17. What is the difference between a parameter and an argument?

Answer

Correct Answer: A parameter is a variable in the declaration of a function. An argument is the value of this variable that gets passed to the function.

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18. What does the value (0.5,0.5,0.5) indicate in the class diagram specification position: Coordinate = (0.5,0.5,0.5)?

Answer

Correct Answer: A default value of the position attribute

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19. What is the best example of a superclass and subclass relationship?

Answer

Correct Answer: Car:toyota

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20. Are you required to return an object if it was passed by reference to a function, and why or why not?

Answer

Correct Answer: No, changes will be automatically reflected in the calling function.

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21. Which type of function can be used for polymorphism?

Answer

Correct Answer: Virtual function

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22. _ describes an aggregation

Answer

Correct Answer: A collection of objects

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23. There are five classes. Class E is derived from class D, D from C, C from B, and B from A. Which class constructor(s) will be called first if the object of E or D is created?

Answer

Correct Answer: A

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24. What defines the catch block most accurately?

Answer

Correct Answer: The catch block that will be executed is the one that best matches the type of exception thrown.

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25. What is a copy constructor?

Answer

Correct Answer: It is a unique constructor for creating a new object as a copy of an object that already exists. There will always be only one copy constructor that can be either defined by the user or the system.

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26. Why would you override a method of a base class?

Answer

Correct Answer: To define a custom implementation of an inherited member

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27. The open/closed principle states that classes should be open for _ but closed for _.

Answer

Correct Answer: Extension; modification

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28. How do object behaviour and attributes differ?

Answer

Correct Answer: Attributes describe a state; behaviours describe a change.

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29. Why is unit testing harder in OOP than functional programming?

Answer

Correct Answer: Objects may maintain internal state, which is not easily accessible by the tests.

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30. What is a reference to an object?

Answer

Correct Answer: It is the address where the variables and methods of an object are stored.

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31. Which of these keywords are access specifiers?

Answer

Correct Answer: Public and private

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32. What is the relationship between abstraction and encapsulation?

Answer

Correct Answer: Abstraction is about making relevant information visible, while encapsulation enables a programmer to implement the desired level of abstraction.

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33. What type of inheritance may lead to the diamond problem?

Answer

Correct Answer: Multiple

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34. Can abstract classes be used in multilevel inheritance?

Answer

Correct Answer: Yes, always

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35. What best describes what object-oriented programming does?

Answer

Correct Answer: It focuses on objects that interact cleanly with one another.

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36. Which words in the following list are candidates for objects: trumpet, clean, enrage, leaf, tree, collapse, active, and lively?

Answer

Correct Answer: Leaf, tree, and trumpet

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37. Which type of function among the following shows polymorphism?

Answer

Correct Answer: Virtual function

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38. In addition to attributes and behaviours, what quality must a class possess?

Answer

Correct Answer: A name

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39. Why is inheritance used when creating a new class?

Answer

Correct Answer: To avoid writing duplicate code
To separate class behavior from the more general

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40. Which is false for a member function of a class?

Answer

Correct Answer: Member functions do not need to be declared inside the class definition.

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41. What is the result of using more abstraction?

Answer

Correct Answer: It can limit code readability

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42. Which statement about compositions and aggregations is true?

Answer

Correct Answer: If a composition dies, the contents die

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43. How are contents of a composition different from those of aggregation?

Answer

Correct Answer: If a composition dies, the contents die

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44. What are CRC Cards?

Answer

Correct Answer: Class Responsibility collaboration cards are a brainstorming tool used in the design of oop software

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45. What is the purpose of static constructor?

Answer

Correct Answer: To initialize all the members with static value

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46. When and how often is a static constructor called?

Answer

Correct Answer: It is called initially when an object is created and only one time.

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47. Why is code duplication so insidious?

Answer

Correct Answer: One has to maintain all the duplicates.

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48. Which is NOT one of the basic types of inheritance?

Answer

Correct Answer: Double inheritance

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49. Which class has the highest degree of abstraction in a multilevel inheritance relationship of five levels?

Answer

Correct Answer: The class at the first level

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50. What is a method?

Answer

Correct Answer: The exact same thing as a function and subroutine

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51. If an object is passed by reference, the changes made in the function are reflected _.

Answer

Correct Answer: To the main object of the caller function, too

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52. In multilevel inheritance, one class inherits how many classes?

Answer

Correct Answer: One class only

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53. What are the five Creational Design patterns by the Gang of Four ?

Answer

Correct Answer: Abstract Factory, Builder, Factory Method, Prototype, and Singleton.

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54. Two classes combine private data members and provide public member functions to access and manipulate those data members. Where is abstraction used?

Answer

Correct Answer: Abstraction is using public member functions to access and manipulate the data members.

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55. A language that does not support polymorphism but supports classes is considered what?

Answer

Correct Answer: An object-based language

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56. Which type of inheritance must be used so that the resultant is hybrid?

Answer

Correct Answer: Multiple

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57. How are user stories different from use cases?

Answer

Correct Answer: User Stories are shorter and less detailed.

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58. In context of OOP, what is association?

Answer

Correct Answer: Association is a relationship where all objects have their own life cycle and there is no owner.

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59. Which of the following is NOT an advantage of using getters and setters?

Answer

Correct Answer: Getters and setters can speed up compilation.

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60. Which statement is true?

Answer

Correct Answer: A default parameter's constructor is not equivalent to the default constructor

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61. Which type of inheritance ,when done continuously, is similar to a tree structure?

Answer

Correct Answer: Hierarchical

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62. Why would you implement composition using an id instead of a reference?

Answer

Correct Answer: All of these answers

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63. Which two blocks are used to handle and check errors?

Answer

Correct Answer: Try and catch

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64. F a local class is defined in a function, what is true for an object of that class?

Answer

Correct Answer: The object can be accessed, declared, and used locally in that function.

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65. When is a constructor executed?

Answer

Correct Answer: When an object is created from a class using the new keyword

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66. Which type of constructor cannot have a return type?

Answer

Correct Answer: Constructors do not have a return type

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67. Which code creates a new object from the Employee class?

Answer

Correct Answer: Employee currentEmployee = new Employee();

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68. What is an IS-A relationship?

Answer

Correct Answer: A subclass object has an IS-A relationship with its superclass or interface

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69. What is encapsulation?

Answer

Correct Answer: Hiding the data and implementation details within a class

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70. What is the best reason to use a design pattern?

Answer

Correct Answer: It will result in code that is more extensible and maintainable

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71. When does static binding happen?

Answer

Correct Answer: At compile time

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72. Why would you create an abstract class, if it can have no real instances?

Answer

Correct Answer: To avoid redundant coding in children

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73. For which case would the use of a static attribute be appropriate?

Answer

Correct Answer: The weather conditions for each house in a small neighborhood

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74. What is an example of dynamic binding?

Answer

Correct Answer: Method overriding

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75. A(n) ____ is a variable that is used within a function.

Answer

Correct Answer: Parameter

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76. A class and its members can be described graphically using a notation known as the ____ notation.

Answer

Correct Answer: UML

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77. In a sequence diagram, the _____ indicates when an object sends or receives a message.

Answer

Correct Answer: Request link

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78. In oop, you declare a class that extends another class. this is called ________.

Answer

Correct Answer: Inheritance

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79. A ____ method is also known as a help method.

Answer

Correct Answer: Work

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80. Class ________ represents an image that can be displayed on a jlabel.

Answer

Correct Answer: ImageIcon

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81. By convention, a class diagram contains the ____ following each attribute or method.

Answer

Correct Answer: Data type

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82. ________ members of a base class are never accessible to a derived class.

Answer

Correct Answer: Private

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83. Protected members of a base class are like ________, but they may be accessed by derived classes.

Answer

Correct Answer: Private members

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84. The ________ class constructor is called before the ________ class constructor.

Answer

Correct Answer: Base, derived

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85. When an object of one class is a data field within another class, they are related by ____.

Answer

Correct Answer: Composition

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86. Multiple inheritance is when a ________ class has ________ base classes.

Answer

Correct Answer: Derived, two or more

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