Deck 9: Using Classes and Objects

Question 1

What do accessors do within the C# language?

A) They define how an instantiation of a class behaves.
B) They control access to the various properties of a class.
C) They provide access to a field of a class.
D) They specify the statements that execute when a class's fields are accessed.

Answer 1

D

Question 2

Predefined types such as int, double, and char are all examples of what component of the C# language?

A) reference types
B) value types
C) output types
D) pointer types

Answer 2

B

Question 3

You can overload an operator for a built-in data type.For example, you can change the meaning of + between two ints.

Answer 3

False

Question 4

Where are the data components of a class that differ for each object stored?

A) Inside of instance variables.
B) In variable unit states.
C) Inside constants
D) Inside parent object relationships.

Question 5

Only nonstatic methods receive a this reference.

Question 6

What reference is passed implicitly and invisibly to every instance method and property accessor?

A) static
B) object
C) use
D) this

Question 7

Besides being known as a class client, what is a class that instantiates objects of another prewritten class known as?

A) a class state
B) a class instantiation
C) a class user
D) a server class

Question 8

What is another name used for instance variables in order to help distinguish them from other variables you might use?

A) states
B) relationships
C) instantiations
D) fields

Question 9

What class access modifier should you utilize to limit access to the assembly (a group of code modules compiled together) to which the class belongs?

A) private
B) internal
C) protected
D) public

Question 10

What class access modifier means that access to the class is not limited?

A) protected
B) private
C) internal
D) public

Question 11

What happens if you do not explicitly include an access specifier?

A) Its access modifier will be public by default.
B) It will be assumed as an internal field.
C) Its access modifier will be private by default.
D) It will be set to protected.

Question 12

If you don't write a constructor for a class object, C# writes one for you.

Question 13

A GUI object, such as a Button, is represented as an object that cannot encapsulate any methods.

Question 14

What class access modifier is used to indicate that access is limited to another class to which the class belongs?

A) private
B) internal
C) protected
D) public

Question 15

A parameter that is undeclared and that gets its value automatically is considered to be what type of parameter?

A) implicit
B) explicit
C) instance
D) property

Question 16

What class access modifier can be used to indicate that access to the class is limited to the class and to any classes derived from the class?

A) internal
B) private
C) protected
D) public

Question 17

Using private fields within classes is an example of what feature found in all object-oriented languages?

A) information hiding
B) polymorphism
C) inheritance
D) overloading

Question 18

When you create an array of objects, the array holds the actual value of each of the objects.

Question 19

What kind of constructor takes no arguments whatsoever?

A) object constructor
B) default constructor
C) construct initializer
D) construct array

Question 20

What are the set of attributes of an object's instance variable known as?

A) The object's relationship.
B) The object's state.
C) The object's class instantiation.
D) The object's fields.

Question 21

Like any other C# method, constructors can be overloaded.Show how to create two public constructors-one with no parameters, and one with a parameter called sal-that both set the value for the property Salary within the following class:
class Employee
{
public double Salary;
}

Question 22

What statement regarding the use of destructors is accurate?

A) A destructor performs actions when a class is instantiated.
B) A destructor must be explicitly created.
C) To declare a destructor, you must use a dash - followed by the class name.
D) You cannot provide any arguments to a destructor.

Question 23

Classes that support simple data items each contain a method that provides the details of how items in the class compare to each other.What is the name of this method?

A) Equals()
B) Less()
C) IndexOf()
D) CompareTo()

Question 24

A member of a class that provides access to a field of a class is referred to as what?

A) implicit parameter
B) property
C) explicit parameter
D) reference type

Question 25

What consists of abstract methods (and perhaps other members) that can be used by any class, as long as the class overrides the abstract method definitions?

A) A C# multifile assembly.
B) A defined framework.
C) A properly implemented interface.
D) A class destructor.

Question 26

Creating an object requires two steps that are shown in the example below:
Employee myAssistant;
myAssistant = new Employee();
What do these statements accomplish?

Question 27

What contains the actions you require when an instance of a class is destroyed, such as when the instance goes out of scope?

A) class constructor
B) constructor initializer
C) destructor
D) parameterless constructor

Question 28

What interface in C# contains the definition for the CompareTo() method that compares one object to another and returns an integer?

A) IComparable
B) Comparable
C) ICompareTo
D) CompareTo

Question 29

What kind of property is one in which the code within the accessors is created automatically?

A) auto-implemented property
B) polymorphic property
C) dynamic property
D) abstract property

Question 30

The Sort() method accepts an array as a parameter and arranges its elements in descending order.What complication arises when you sort an array of objects? Explain how to use the IComparable interface to address this problem.

Question 31

Even though you can't specify this modifier for a named constant within a class, what is the effective access modifier for the constant?

A) public
B) private
C) static
D) internal

Question 32

What happens when a method overrides another method?

A) It instantiates that method and takes over its properties.
B) It takes precedence over the original method, hiding it.
C) It overloads the original method, allowing for varying parameters.
D) It extends the original method, adding additional functionality.

Question 33

Explain what a destructor is and why it cannot be overloaded.

Question 34

As an alternative to repeating code in multiple constructors, what can be used to indicate that another instance of a class constructor should be executed before any statements in the current constructor body?

A) parameterless constructor
B) value constructor
C) constructor initializer
D) default constructor

Question 35

Briefly explain how to create instance variables, and show how to define a private integer instance variable called idNumber within a class called Employee.

Question 36

What are the class access modifiers in C#?

Question 37

Write an example method that overrides the + operator to create a new book whose title is a concatenation of the titles of two books.For example, if the first book's title is "The Adventures of Tom Sawyer" and the second book's title is "The Adventures of Huckleberry Finn", the concatenated title will be "The Adventures of Tom Sawyer and The Adventures of Huckleberry Finn".Assume the book class is defined as:
class Book
{
public Book(string title)
{
Title = title;
}
public string Title {get; set;}
}

Question 38

Briefly describe what an object initializer does and give a specific example.When is the object initializer assignment made?

Question 39

What is the difference between overriding a method and overloading a method with respect to method signatures?