Table of contents
Preface
This module is part of a self-assessment test designed to help you determine how much you know about object-orientedprogramming using Java.
The test consists of a series of questions with answers and explanations of the answers.
The questions and the answers are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back.
I recommend that you open another copy of this document in a separate browser window and use the links to under Listings to easily find and view the listings while you are reading about them.
Questions
Question 1 .
What output is produced by the program shown in Listing 1 ?
- A. Compiler Error
- B. Runtime Error
- C. 9 17.64
- D. None of the above
| Listing 1 . Listing for Question 1. |
|---|
public class Ap079{
public static void main(String args[]){new Worker().doOverLoad();
}//end main()}//end class definition
class Worker{public void doOverLoad(){
int x = 3;double y = 4.2;
System.out.println(square(x) + " "+ square(y));
}//end doOverLoad()public int square(int y){return y*y;
}//end square()public double square(double y){return y*y;
}//end square()}// end class |
Question 2
What output is produced by the program shown in Listing 2 ?
- A. Compiler Error
- B. Runtime Error
- C. float 9.0 double 17.64
- D. None of the above
| Listing 2 . Listing for Question 2. |
|---|
public class Ap080{
public static void main(String args[]){new Worker().doOverLoad();
}//end main()}//end class definition
class Worker{public void doOverLoad(){
int x = 3;double y = 4.2;
System.out.print(square(x) + " ");System.out.print(square(y));
System.out.println();}//end doOverLoad()public float square(float y){
System.out.print("float ");return y*y;
}//end square()public double square(double y){System.out.print("double ");
return y*y;}//end square()
}// end class |
Question 3
What output is produced by the program shown in Listing 3 ?
- A. Compiler Error
- B. Runtime Error
- C. 10 17.64
- D. None of the above
| Listing 3 . Listing for Question 3. |
|---|
public class Ap081{
public static void main(String args[]){new Worker().doOverLoad();
}//end main()}//end class definition
class Worker{public void doOverLoad(){
double w = 3.2;double x = 4.2;int y = square(w);
double z = square(x);System.out.println(y + " " + z);}//end doOverLoad()public int square(double y){
return (int)(y*y);}//end square()public double square(double y){
return y*y;}//end square()
}// end class |
Question 4
What output is produced by the program shown in Listing 4 ?
- A. Compiler Error
- B. Runtime Error
- C. 9 17.64
- D. None of the above
| Listing 4 . Listing for Question 4. |
|---|
public class Ap083{
public static void main(String args[]){new Worker().doOverLoad();
}//end main()}//end class definition
class Worker{public void doOverLoad(){
int w = 3;double x = 4.2;
System.out.println(new Subclass().square(w) + " "
+ new Subclass().square(x));}//end doOverLoad()
}// end classclass Superclass{
public double square(double y){return y*y;
}//end square()}//end class Superclass
class Subclass extends Superclass{public int square(int y){
return y*y;}//end square()
}//end class Subclass |