CSC 101 / CPE 101:
Fundamentals of Computer Science 1

Part 1: Testing your CaesarCipher program

Download these files to your lab-practice folder:

• secret1.txt
• secret2.txt
• secret3.txt
• secret4.txt
• secret5.txt

Execute these commands until you cannot read the text that results (note: if your program loops, asking the person if they want to try another set, each of these will fail at that point -- that is acceptable; the question is whether you can read the secret message before that error (i.e., you decode it correctly) or whether your program balks at even trying to decode it (i.e., it doesn't work right on even the first round) as specified):

• java SimpleCaesar <secret1.txt
• java SimpleCaesar <secret2.txt
• java SimpleCaesar <secret3.txt
• java SimpleCaesar <secret4.txt
• java SimpleCaesar <secret5.txt

Once you know on how many of these your code does work, then repeat the exercise, executing the following commands exactly. Take care with spaces and non-alphabetic characters (you should not see any output unless you type out the contents of the plain.txt file):

• java SimpleCaesar <secret1.txt  >plain.txt
• java SimpleCaesar <secret2.txt >>plain.txt
• java SimpleCaesar <secret3.txt >>plain.txt
• java SimpleCaesar <secret4.txt >>plain.txt
• java SimpleCaesar <secret5.txt >>plain.txt

Print the file plain.txt (open it in pfe and print from there, if need be). Write your name on it, and hand it in. Staple to it a copy of your code for this lab and hand that in. (This part should take you less than half the lab period! Hand this much in before the end of this lab period: no late-submissions will be counted towards this lab's grade).

FYI: #1 tests the basic lab requirements; #2 tests an oversize key (i.e., greater than the number of letters in the plain alphabet); #3 and #4 test negative keys (a special case, and a more general case, respecively, which will give clues to the approach your code used); and #5 tests an oversize negative key (it will not work if either #2 or #4 fail). For a passing grade at all, your code should handle #1. To meet the general specs in the lab write-up, it should also handle #2. The others are extra features, for those of you who think you have really mastered this activity (worth correspondingly higher grades).

Part 2: Practice with 2-D arrays

Write a class, with its own driver, that does the following:

• Instantiates, in the driver method,
  • an integer array of student quiz scores;
  • a String array of student names (Art, Betty, Carl);
  • Use this data for the students:

    87	93	91	88	81	98
    81	85	91	88	94	97
    99	72	93	71	95	85

• Contains a method averageAcrossStudents that accepts that array as a parameter, and returns a floating point array that represents the average score for each student (row);
• Contains a method averageAcrossQuizzes that accepts that array as a parameter, and returns a floating point array that represents the average score for each quiz (column);
• In the driver method, uses the result from averageAcrossStudents() to print each student's name and hi/r overall average grade;
• In the driver method, uses the result from averageAcrossQuizzes to print the average grade scored by all students for each quiz.

Run the file, and append a sample run as a comment at the end of your code. Print that out (the code plus the sample run), and hand that in before the end of lab (full credit) or at the START of your next lecture (10% penalty). Note: there will be an entirely different activity to work on during lab on Thursday.