Quiz 2 [Object-Oriented Programming]

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Quiz on Quiz 2 [Object-Oriented Programming], created by marinathepichu on 09/04/2016.
marinathepichu
Quiz by marinathepichu, updated more than 1 year ago
marinathepichu
Created by marinathepichu over 8 years ago
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Resource summary

Question 1

Question
What are the three main features of object-oriented programming? (pick 3)
Answer
  • abstraction
  • encapsulation
  • inheritance
  • methods
  • polymorphism
  • recursion

Question 2

Question
A(n) _______ is a type that references a method.
Answer
  • modifier
  • accessor
  • class
  • delegate

Question 3

Question
A class that does not provide a complete implementation must be declared with the keyword _________.
Answer
  • abstract
  • static
  • inc
  • delegate

Question 4

Question
You are writing a code to handel events in your protram. You define a delegate named RectangleHandler like this: public delegate void RectangleHandler(Rectangle rect); you also create a variable of the RectangleHandler type as follows: RectangleHandler handler; Later in the program, you need to add a method named DisplayArea to the methodinvocation list of the handler variable. The signature of the DisplayArea method matches the signature of the RectangleHandler method. Any code that you write should not affect any existing event-handling code. Given this restriction, which of the following codes should you write?
Answer
  • handler = DisplayArea;
  • handler = new RectangleHandler(DisplayArea);
  • hander -= DisplayArea;
  • handler += DisplayArea;

Question 5

Question
A(n) _______ is a blueprint of an object.
Answer
  • class
  • method
  • variable
  • flowchart

Question 6

Question
You are writing code for a class named Product. You need to make sure that the data members of the class are initialized to their correct values as soon as you create an object of the Product class. The initialization code should be always executed. What should you do?
Answer
  • Create a constructor in the Product class to initialize data members.
  • Create an event in the Product class to initialize data members.
  • Create a static property in the Product class to initialize data members.
  • Create a static method in the Product class to initialize data members.

Question 7

Question
You want to restrict the access for a method to the containing class or to a class that is derived from the containing class. Which access modifier should you use for this method?
Answer
  • protected
  • private
  • internal
  • public

Question 8

Question
The _______ keyword refers to the current instance of a class.
Answer
  • this
  • that
  • current
  • thing

Question 9

Question
You can use ______ to group related classes in order to reduce name collisions.
Answer
  • namespace
  • encapsulation
  • struct
  • private

Question 10

Question
You defined a class AdvMath that defines advanced mathematical functionality. You plan to make classes that are derived from AdvMath. You do not want the functionality of AdvMath class to be inherited into derived classes. What keyword should you use to define the AdvMath class?
Answer
  • private
  • internal
  • abstract
  • sealed

Question 11

Question
You are creating a new class named Circle. You write the following code: class Circle: IComparable { public double Radius{ get; set; } public double GetArea() { return Radius*Radius*3.14159 } public int CompareTo(object obj) { // some code will go here... } }
Answer
  • /************************************************ public int CompareTo(object obj) { Circle target = (Circle)obj; double diff = this.GetArea() - target.GetArea(); if(diff ==0) return 0; else if (diff > 0) return 1; else return -1; } /*******************************************************
  • /************************************************ public int CompareTo(object obj) { Circle target = (Circle)obj; if(this==target) return 1; else if (diff > 0) return -1; else return 0; } /*******************************************************
  • /************************************************ public int CompareTo(object obj) { Circle target = (Circle)obj; double diff = this.GetArea() - target.GetArea(); if(diff ==0) return 1; else if (diff > 0) return -1; else return 0; } /*******************************************************
  • /************************************************ public int CompareTo(object obj) { Circle target = (Circle)obj; if(this==target) return 0; else if (diff > 0) return 1; else return -1; } /*******************************************************

Question 12

Question
Which of the following class elements should you use to define the behavior of a class?
Answer
  • method
  • event
  • property
  • delegate

Question 13

Question
You can use the _____ keyword to declare a member that belongs to the class itself rather than to a specific object.
Answer
  • static
  • public
  • private
  • limited

Question 14

Question
You can use the ______ operator to check whether it is legal to cast one type to another type.
Answer
  • is
  • try
  • castTo
  • =

Question 15

Question
INCOMPLETE The Draw() method in the Square class should provide new functionality but also hide the Polygon class implementation of the Draw() method. Which line of code would accomplish this?
Answer
  • INCORRECT public static void Draw()
  • INCORRECT public virtual void Draw()
  • public new void Draw()
  • public override void Draw()

Question 16

Question
INCOMPLETE You need to provide query functionality to several of your classes. Each class's algorithm for the query will likely be different. Also, not all the classes have an "is-a" relationship with each other. How should you support this functionality?
Answer
  • INCORRECT Have all the classes inherit from an abstract base class and override the base-class method to provide their own query functionality.
  • Create a common interface that is implemented by all the classes.
  • Have all the classes inherit from a base classes that provides the query functionality.
  • Add the query functionality to a base class with the public access modifier.

Question 17

Question
INCOMPLETE You are writn code for a new method named Process: void Process (object o) { //code goes here... } The code received a parameter of type object. You need to cast this object into the type Rectangle. At times, the value of o that is passed to the method might not be a valid Rectangle value. You need to make sure that the code does not generate any System.InvalidCastExpection errors while doing the conversion. Which of the following lines of code should you use inside the Process method to accomplish this goal?
Answer
  • INCORRECT Rectangle r = o is Rectangle;
  • Rectangle r = (o != null) ? o as Rectangle: (Rectangle) o;
  • Rectangle r = o as Rectangle;
  • Rectangle r = Rectangle) o;

Question 18

Question
INCOMPLETE Classes that want to support comparison must implement the IComparable interface and then provide a body for the _______ method.
Answer
  • INCORRECT ==
  • CompareTo
  • Main
  • isA

Question 19

Question
INCOMPLETE In a class, you defined a method called Render. This method provides functionality to render bitmap files on a the screen. You would like the derived classes to supersede this functionality to support the rendering of additional image formats. You also want the Render method of the derived classes to be executed even if a derived class is cast as the base class. Which keyword should you use with the definition of the Render method in the base class?
Answer
  • INCORRECT abstract
  • INCORRECT overrides
  • new
  • virtual

Question 20

Question
INCOMPLETE Which of the following are value types (not reference types)? choose all that apply.
Answer
  • float
  • struct
  • INCORRECT string
  • INCORRECT class
  • int
  • method
  • INCORRECT delegate
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