1
e01b
CS56 F17
DO NOT WRITE IN THIS AREA! Name: Seat:
(as it would appear on official course roster)
Umail address: @umail.ucsb.edu

EXAM: e01b: Practice Midterm Exam 'B'

ready? date points
true Thu 07/07 09:30AM

You may not collaborate on this exam with anyone. If you need to use the restroom, you must leave your cell phone with the exam proctor before leaving the room.

  • Write your name at the top of this page AND EVERY ODD NUMBERED PAGE.
  • Double check that you turned in ALL pages; look for "End of Exam" on the last page.
  • This exam is closed book, closed notes, closed mouth, cell phone off.
  • You are permitted one sheet of paper (max size 8.5x11") on which to write notes.
  • This sheet will be collected with the exam, and might not be returned.
  • Please write your name on your notes sheet.

Note: This is not a “complete” 100 point practice exam. This is a place I’ll put additional example problems as I encounter them between now and the exam on Thursday.

For a full 100 point practice exam, click here..

  1. (20 pts) For practice exam purposes: This exercise is a variation on the exercise on p. 266 in HFJ. The answer to that one appears in the book, so I suggest you try that one first, then check your answer before attempting this problem.

    On the handout there is some code. Your job: figure out after which line of main() each of the following objects is eligible for garbage collection.

    If an object is still not eligible for garbage collection when the last line of main is reached, write “never”. Your answer should be one of the line numbers that appears in comments in main (e.g. /* 3 */ or /* 7 */) or the word “never”.

    Object Fill in line here
    (a) Fido  
    (b) Rover  
    (c) Princess  
    (d) Spot  
    (e) Snoopy  
  2. (Problem 12 from CS56 W12 Midterm 2) For this question, you need the additional handout with code for these files: Book.java, Product.java, Shippable.java, Song.java.

    You may assume that all of the code for Question 2 on the handout compiles—I’ve checked that this is true. Now consider the code for the Q2 class below, which does contain some errors, and as a result, will NOT compile.

    Please do these things with this “broken” code for the Q2 class:

    1. (10 pts) Several lines need to be eliminated from this file in order to make it compile. Find the lines that are bogus, and draw a line through each of them in the code listing above. Hint: By “several”, I mean more than 2, and fewer than 10. Start by determining which, if any, of the constructors are bogus. Then, eliminate any lines that refer to the variables created on those lines. Finally, check all of the remaining method calls.

      You will lose two points each time you striking a line that is not bogus, and you will lose two points for failing to strike any line that IS bogus. So, choose wisely.

      /* 1*/	public class Q2 {
      /* 2*/	  public static void main (String [] args) {
      /* 3*/	    
      /* 4*/      Book gp = new Book("Pratchett","Going Postal",799,0.15);
      /* 5*/      Song br = new Song("Lady Gaga","Bad Romance");
      /* 6*/      Product slts = new Song("Nirvana","Smells Like Teen Spirit",79);
      /* 7*/      Shippable hp = new Book("Rowling","Harry Potter & the Polymorphic Polyp",652,1.5);
      /* 8*/      Shippable ttc = new Shippable("Dickens","Tale of Two Cities",999,1.5);
      /* 9*/ 					       
      /*10*/      System.out.println("a:" + gp.getTitle());
      /*11*/      System.out.println("b:" + br.getArtist());
      /*12*/      System.out.println("c:" + br.getPrice());
      /*13*/      System.out.println("d:" + slts.getPrice());
      /*14*/      System.out.println("e:" + slts.getTitle());
      /*15*/      System.out.println("f:" + hp.getPrice());
      /*16*/      System.out.println("g:" + hp.getWeight());
      /*17*/      System.out.println("h:" + hp.getTitle());
      /*18*/      System.out.println("i:" + ttc.getPrice());
      /*19*/      System.out.println("j:" + ttc.getPrice());
      /*20*/ 
      /*21*/    } // main method
      /*22*/ } // class Q2
      
      
    2. (10 pts) After striking through the bogus lines, the remaining code should compile and run. So, indicate what the output will be (if any) below. Be precise. If there will no output, write “no output”.

http://ucsb-cs56-m16.github.io/exam/e01/cs56_m16_e01_practice_b/

End of Exam