OOPs VB .Net Quiz

Description: OOPs VB .Net Quiz
Number of Questions: 13
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Tags: .net vb oop
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Inheritance makes it easier to:

  1. reuse and modify existing modules of code.

  2. write and read code by sharing method names.

  3. hide and protect data from external code.

  4. Both a and b.

  5. All of the above.


Correct Option: A

AI Explanation

To answer this question, you need to understand the concept of inheritance.

Inheritance is a fundamental concept in object-oriented programming (OOP) that allows a class to inherit properties and methods from another class. It creates a parent-child relationship between classes, where the child class inherits the attributes and behaviors of the parent class.

Now let's go through each option to understand why it is correct or incorrect:

Option A) Reuse and modify existing modules of code - This option is correct because inheritance allows us to reuse and modify existing code by inheriting the properties and methods of a parent class. We can create new classes based on existing ones, without having to rewrite the code from scratch. This promotes code reusability and reduces redundancy.

Option B) Write and read code by sharing method names - This option is not applicable to inheritance. While inheritance does allow sharing method names between parent and child classes, it is not the primary purpose of inheritance. Sharing method names can be achieved through other mechanisms as well, such as interfaces or implementing common interfaces.

Option C) Hide and protect data from external code - This option is not applicable to inheritance. Hiding and protecting data is achieved through encapsulation, which is a different concept in OOP. Inheritance focuses on code reuse and the relationship between classes, rather than data hiding.

Option D) Both a and b - This option is incorrect because option B is not a valid reason for inheritance.

Option E) All of the above - This option is incorrect because option C is not a valid reason for inheritance.

The correct answer is option A. Inheritance makes it easier to reuse and modify existing modules of code by inheriting properties and methods from a parent class.

Polymorphism makes it easier to:

  1. reuse and modify existing modules of code.

  2. write and read code by sharing method names.

  3. hide and protect data from external code.

  4. Both a and b.

  5. All of the above.


Correct Option: B

The standard prefix to signify a class is:

  1. B

  2. C

  3. L

  4. S

  5. T


Correct Option: E

AI Explanation

To answer this question, we need to understand the standard prefix used to signify a class.

Option A) B - This option is incorrect because "B" is not a standard prefix used to signify a class.

Option B) C - This option is incorrect because "C" is not a standard prefix used to signify a class.

Option C) L - This option is incorrect because "L" is not a standard prefix used to signify a class.

Option D) S - This option is incorrect because "S" is not a standard prefix used to signify a class.

Option E) T - This option is correct because "T" is the standard prefix used to signify a class.

The correct answer is E) T. This option is correct because "T" is the standard prefix commonly used to signify a class.

When using encapsulation how should data be shared with external code?

  1. Events

  2. Methods

  3. Properties

  4. Private variables

  5. Public variables


Correct Option: C

AI Explanation

To answer this question, you need to understand encapsulation and how data should be shared with external code.

Encapsulation is a principle in object-oriented programming that bundles data and the methods that operate on that data into a single unit, called an object. It allows for the implementation details of an object to be hidden from external code, providing a clean interface for interacting with the object.

When using encapsulation, data should be shared with external code through properties. Properties provide a controlled way of accessing and modifying the internal state of an object. They allow for the implementation details of the data to be hidden, while providing public access to it.

Option A) Events - Events are used to notify external code about certain actions or changes that occur within an object. While events can be used to share information, they are not the primary means of sharing data with external code in encapsulation.

Option B) Methods - Methods are used to perform operations on the data within an object. While methods can indirectly access and modify the data, they are not the primary means of sharing data with external code in encapsulation.

Option C) Properties - Properties provide a way to encapsulate data and provide controlled access to it. This is the correct option. With properties, the internal state of an object can be hidden, while still allowing external code to read and write the data through defined getter and setter methods.

Option D) Private variables - Private variables are used to store the internal state of an object. They are not directly accessible from external code and are typically accessed and modified through getter and setter methods. While private variables are used in encapsulation, they are not the primary means of sharing data with external code.

Option E) Public variables - Public variables are directly accessible from external code. However, exposing data through public variables violates the principle of encapsulation, as it allows external code to directly manipulate the internal state of an object. Therefore, using public variables is not the recommended approach for sharing data with external code in encapsulation.

The correct answer is C) Properties. This option is correct because properties provide a controlled way of sharing data with external code while maintaining encapsulation.

Which statement is true?

  1. A base class inherits some of the properties of a derived class.

  2. A base class inherits all of the properties of a derived class.

  3. A derived class inherits some of the properties of a base class.

  4. A derived class inherits all of the properties of a base class.

  5. None of the above.


Correct Option: D

AI Explanation

To answer this question, you need to understand the concept of inheritance in object-oriented programming.

Inheritance is a mechanism in object-oriented programming that allows a class to inherit properties and methods from another class. The class that is being inherited from is called the base class (or parent class), and the class that inherits from the base class is called the derived class (or child class).

Let's go through each option to understand why it is correct or incorrect:

Option A) A base class inherits some of the properties of a derived class. This option is incorrect because in inheritance, it is the derived class that inherits properties from the base class, not the other way around.

Option B) A base class inherits all of the properties of a derived class. This option is incorrect because in inheritance, it is the derived class that inherits properties from the base class, not the other way around.

Option C) A derived class inherits some of the properties of a base class. This option is incorrect because in inheritance, a derived class inherits all the properties of the base class.

Option D) A derived class inherits all of the properties of a base class. This option is correct because in inheritance, a derived class inherits all the properties and methods of the base class.

Option E) None of the above. This option is incorrect because option D is the correct answer.

Therefore, the correct answer is option D. A derived class inherits all of the properties of a base class.

  1. there is no effect on the derived class.

  2. the derived class changes when the key word Overridden is used.

  3. only the methods of the derived class change.

  4. only the properties of the derived class change.

  5. the derived class automatically changes.


Correct Option: E

Polymorphism can apply to:

  1. math operators.

  2. method names.

  3. object names.

  4. Both a and b.

  5. All of the above.


Correct Option: D

With polymorphism:

  1. one method can have multiple names.

  2. one object can have multiple names.

  3. many methods can share the same name.

  4. many objects can share the same name.

  5. None of the above statements are true.


Correct Option: C
Explanation:

To understand the concept of polymorphism, it's important to have knowledge of object-oriented programming and the principles of inheritance and method overriding. Polymorphism is a concept in object-oriented programming that allows objects of different classes to be treated as objects of a common superclass. This concept enables different classes to have methods with the same name, but different implementations.

Now, let's go through each statement and explain whether it is true or false:

A. one method can have multiple names: This statement is false. In polymorphism, multiple methods can have the same name, but they must have different parameter lists or be defined in different classes.

B. one object can have multiple names: This statement is false. An object can have one name and can be referred to by a single reference variable.

C. many methods can share the same name: This statement is true. Polymorphism allows multiple methods with the same name but different parameter lists to be defined in different classes or even within the same class.

D. many objects can share the same name: This statement is false. Each object has a unique identity and is referred to by a specific reference variable.

E. None of the above statements are true: This statement is false. Statement C, "many methods can share the same name," is true.

So, the correct answer is C. Many methods can share the same name.

I hope this clarifies the concept of polymorphism for you. Let me know if you have any further questions.

Which element of a class is optional?

  1. Constructs

  2. Fields

  3. Methods

  4. Properties

  5. All of the above.


Correct Option: E
Explanation:

A class can have any combination of the following elements:

  • Constructs: These are special methods that are used to initialize an object. They are not required, but they are often used.
  • Fields: These are variables that are associated with an object. They are not required, but they are often used to store data about the object.
  • Methods: These are functions that are associated with an object. They are not required, but they are often used to perform operations on the object.
  • Properties: These are a way to access and modify the fields of an object. They are not required, but they can make the code more readable and maintainable.

Therefore, the answer to the question is E. All of the above. Any of these elements can be optional in a class.

What is the suggested order for the definition of class elements from first to last?

  1. Constructs, fields, methods, properties

  2. Properties, constructs, fields, methods

  3. Fields, properties, constructs, methods

  4. Constructs, properties, fields, methods

  5. Methods, constructs, properties, fields


Correct Option: C

AI Explanation

To answer this question, you need to understand the typical order in which class elements are defined. Let's go through each option to understand why it is correct or incorrect:

Option A) Constructs, fields, methods, properties - This option is incorrect because the order of fields and properties is reversed.

Option B) Properties, constructs, fields, methods - This option is incorrect because the order of constructs and properties is reversed.

Option C) Fields, properties, constructs, methods - This option is correct because it follows the suggested order of defining class elements. Fields are typically defined first, followed by properties, constructs, and methods.

Option D) Constructs, properties, fields, methods - This option is incorrect because the order of fields and properties is reversed.

Option E) Methods, constructs, properties, fields - This option is incorrect because the order of fields and methods is reversed.

The correct answer is C. This option is correct because it follows the suggested order of defining class elements, with fields being defined first, followed by properties, constructs, and methods.

A constructor is a special type of:

  1. class.

  2. field.

  3. method.

  4. property.

  5. variable.


Correct Option: C

Which is true for constructors in a class?

  1. All constructors must have the same number of parameters.

  2. All constructors must be the same parameter data type.

  3. Some constructors can have the same list of parameters.

  4. Only two constructors in a class can have the same list of parameters.

  5. No two constructors in a class can have the same list of parameters.


Correct Option: E

Which statement will call a constructor of a base class?

  1. Base.New( )

  2. BaseConstructor.New ( )

  3. CallBase.New( )

  4. Constructor.New ( )

  5. MyBase.New( )


Correct Option: E
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