Homework 9: Reading Integers

Assigned: Friday, February 17, 2006
Due: 8:00 a.m., Monday, February 20, 2006

Summary: In this assignment, you will rewrite your readInt method.

Purposes: To help you further explore exceptions; To give you the opportunity to improve a method you will regularly call.

Contents:

• Background
• The Assignment
• Submitting Your Work
• Extra Credit

Background

At this point in your Java career, you've regularly written programs that read integers. You've gone from explicitly writing a sequence of lines to using a readInt method that you've written. The basic readInt method is defined as follows:

public static int readInt(PrintWriter pw, BufferedReader br, String prompt)
  throws Exception
{
  pen.print(prompt);
  pen.flush();
  String response = br.readLine();
  return Integer.parseInt(response);
} // readInt(PrintWriter, BufferedReader, String)

Unfortunately, the standard readInt has a number of failings. For example, it does not reprompt the user if the user has entered something that does not seem to be an integer. It also refuses to accept perfectly reasonable responses, like one.

The Assignment

Rewrite readInt so that it is friendlier. In particular,

• If readInt is interactive (that is, it is reading from the keyboard rather than from a file), reprompt for a valid value as long as the user does not enter a valid value.
• Permit words that describe integers. Minimally, you should support one, two, three, four, five, six, seven, eight, and nine.

Submitting Your Work

When you are satisfied with your work, send me the code of readInt. You need not send your enclosing class or test methods.

Extra Credit

There are, as always, a variety of ways with which you can earn extra credit. One of the most natural ways is to support a wider variety of written descriptions of integers (such as one thousand two hundred and twelve or one hundred thousand).