CS 3291 (Java with Internet Applications):
Homework #1

Assigned:

September 10, 1999.

Due:

September 17, 1999, class time.

Credit:

10 points.

Objective:

Define and use a class.

Description:

You are to implement a simple Clock class, with a constructor method and methods to reset the clock, increment its value, and display its value. The template code gives details.

Instructions:

1. Download template source code (Clock.java).
2. Replace comments of the form

   // Your code/declarations go here.

   with declarations and code to implement the methods as described in the comments. Also replace your name, SSN, and e-mail address in the comments at the top of the source code, and (optionally) fill in the "time spent" comment.
3. Test the program until you are satisfied that it works. See Java tips for help with compiling and executing.
4. Submit as described in How to submit homework.

Grading:

This homework is worth 10 points:

• 8 points for correctness. I will evaluate this in two ways:
  1. I will execute your program using command-line arguments as described in the template source code.
  2. I will invoke your class from our test program, to check that your definition conforms to the interface given in the template source code.
• 2 points for programming style. See Programming style for notes on what I consider good programming style. (For this assignment, style should not be much of an issue since you are simply filling in the blanks of the "template" code.)

Helpful hints:

1. Here are some methods you may find useful. These methods are part of the standard language package; you do not need any import statements to use them.
   • Integer.parseInt(String s) returns an integer; e.g. Integer.parseInt("10") returns the integer 10.
   • System.out.print(String s) and System.out.println(String s) print strings to standard output, without and with (respectively) an end-of-line marker. If you call either method with an argument that is not a string, the argument will be converted into a reasonable printable representation and written to standard output.
   • If s1 and s2 are strings, s1.equals(s2) returns a boolean indicating whether the two strings have the same value. (The expression s1 == s2 compares not the values of the strings but the values of the references, and thus yields true only when s1 and s2 are the same object.)
2. Recall that + denotes concatenation when applied to strings, and note that you can convert anything to a string by concatenating it with another string. For example, the value of "ab" + 10 is a string with value "ab10".