ITEC 120 2012fall dbraffitt ibarland

home—info—lects—labs—exams—hws
tutor/PIs—breeze (snow day)
Object120 + its docs—java.lang docs—java.util docs

hw09
arrays
histograms (due Nov.16 (Fri) 11:00)

Complete the following exercises from the textbook. Submit just one program file; include the answers to the written problems as a comment at the start of your program.

• (5pts) Exercise 8.1 (seventh ed.), “Which are valid declarations?”. In Fourth-Sixth ed.: Exercise 7.1. The problem statement will also be posted on D2L.
  Note: The second example should have the square-brackets moved, and it should really use double instead of float. So:
  double[] elapsedTimes = …
  (This has already been incorporated into the version on D2L.)
• (3pts) Exercise 8.4 (seventh ed.), “what problem occurs”. In Fourth-Sixth ed.: Exercise 7.3. The problem statement will also be posted on D2L.
• (32pts) Programming Project 8.4, histogram-printing. In Fourth-Sixth ed.: Programming Project 7.4. The problem statement will also be posted on D2L shortly.
  Your development will presumably pass through the stages of projects 8.1 and 8.3. I strongly recommend having two functions for PP8.1: one which reads input and returns an array; another which takes in an array, and prints out desired info on the screen.
  When upgrading from 8.3 to 8.4, you might find it helpful to read input from a file, which we talked about in lab last Thursday.)
  Unlike the book's Listing 8.3, which has all the code in one big main method, your program must be better organized, including at least three methods:
  • A main driver which allocates and initializes the array, then calls the two methods below.
  • one method which reads numbers from System.in and tabulates the results:
  • A method which prints the histogram for a given array.

  You'll need to think closely about how your program will work, and what appropriate named constants you might use. In particular, when transitioning from project 8.1 to 8.3, you'll have a decision to make make about your data representation (good ol' step 1 of the design recipe).
  As always -- work incrementally: start with small/stub methods, and then gradually add more functionality.

  Develop this program without using BlueJ -- just use a text editor and compile/run your program using the commands javac and java.

  Note that you do not need to handle bad-input entered by the user (e.g. if they type in 101, it's okay for your program is allowed to crash). 3pts extra credit if your program never crashes on any input.

  As long as the output looks similar to what is suggested, it's okay. In particular, the row-headers can be slightly different lengths, due to "1 - 10" being one character shorter than "11 - 20". 3pts extra credit if you make them align.

home—info—lects—labs—exams—hws
tutor/PIs—breeze (snow day)
Object120 + its docs—java.lang docs—java.util docs

©2012, Ian Barland, Radford University Last modified 2012.Nov.18 (Sun)

Please mail any suggestions (incl. typos, broken links) to ibarlandradford.edu