Simple Command Line Handling Programs (Classes)

Due Date: 2/10/03
Electronic Submission Only!

This assignment involves the creation of a number of Java classes, each defined in it's own file. Each class should have a main() method so the class can be run.

IMPORTANT!!! : You have to use the class names specfied here, you can't make up your own names. Java class names are case sentitive. Note that by defining the class names, we are also defining the file names you will submit.

Create a class named SumOfArgs that will print out the sum of all integer arguments found on the command line. Anything that is not an integer should be skipped (should not contribute to the sum). Your progam should print out only the sum (nothing else!). No error messages can be printed out (no matter what the command line args look like). Examples of what your class should do when run:

> java SumOfArgs 
0
> java SumOfArgs 10 9 8
27
> java SumOfArgs hello dave 1 2 3
6
> java SumOfArgs Hello World
0

Create a class named Substring that will expect the first command line argument to be a string, and the second two command line arguments to be integers, the first will be used as an index and the second as a length. The output should be the subtring of string starting at the index and of the specified length. Examples:

> java Substring Jello 1 3
ell
> java Substring "Hello World" 0 5
Hello
> java Substring OneTwoThree 5 1
o

Notes: As you can see from the examples, an index of 0 refers to the first character in the string. To figure out how to extract a substring from a String, check out the API documentation for the class String which can be found in java.lang

Create a class named StringCompare that will be passed two strings on the command line. Your class should print "true" if the two strings are identical when compared without regard to the case of each character (case insensitive comparison). If the strings are not identical (ignoring case), your class should print "false". No error messages should be printed (no matter what, if anything, is specified on the command line). The default output should be "false", so if no strings are specified (or only one), your class should print "false".

> java StringCompare Hello Dave
false
> java StringCompare Hello hello
true
> java StringCompare Hello Hellow
false
> java StringCompare
false

Notes: You really need to get to know about the String class to get this working! You need to be able to convert strings to all lower (or upper case), and then you need to figure out how to compare two strings. Once again, look at the Java documentation for the String class in the java.lang section of the API docs.

Submission of your homework is via email, the general idea is to send an email message with your files as attachments. There is an automated email submission system that will respond to your submission right away, so you will have a record that we got your file. For HW2 you should submit your .java files (one for each class).

All projects must be submitted via email to javaprog-submit@cs.rpi.edu. The subject line of the submission message should contain a single number '2' indicating the HW number. The body of your message should include your full name (and anything else you want to tell us). Make sure your email message includes your full name, we can't record your grade unless we know your name (and the email address joe222@yahoo.com doesn't mean anything to us!).

Don't send compiled code (class files)!

You can expect a return email indicating receipt of your project submission immediately. This receipt will include a list of all the files that were successfully extracted by the submission script - please look over the receipt carefully to make sure your submission worked.

Multiple Submissions: You can resubmit up to 10 times for each project, we will always grade the last submission received unless you tell us otherwise.