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3.1 Instructions
Practice Problems
Problem 1:   Understanding the String class
6.10

Assignment 3: Working with the String class; Designing methods for Complex Data

Goals: Learn to use the String class, practice working with lists. Learn to design methods and practice designing with accumulators.

3.1 Instructions

Be very, very careful with naming! Again, the solution files expect your submissions to be named a certain way, so that they can define their own Examples class with which to test your code. Therefore, whenever the assignment specifies:
  • the names of classes,

  • the names and types of the fields within classes,

  • the names, types and order of the arguments to the constructor,

  • the names, types and order of arguments to methods, or

  • filenames,

...be sure that your submission uses exactly those names.

Make sure you follow the style guidelines that handin enforces. For now the most important ones are: using spaces instead of tabs, indenting by 2 characters, following the naming conventions (data type names start with a capital letter, names of fields and methods start with a lower case letter), and having spaces before curly braces.

You will submit this assignment by the deadline using the handin submission system. You may submit as many times as you wish. Be aware of the fact that close to the deadline the system may have a long queue of submissions which means it takes longer for your code to be submitted - so try to finish early.

There will be a separate submission for each problem - it makes it easier to grade each problem, and to provide you with the feedback for each problem you work on.

The submission will be organized as follows:

WARNING: Be extra careful not to name your file "String.java" – or else Java will think that you’re trying to redefine the built-in String class, and everything will break in creatively bizarre ways.

Due Date:
  • Friday, May 15th, 10:00pm EST

Practice Problems

Work out these problems on your own. Save them in an electronic portfolio, so you can show them to your instructor, review them before the exam, use them as a reference when working on the homework assignments.

Problem 1: Understanding the String class

Related files:
  Strings.java  

For all questions in this problem, be sure to follow the design recipe carefully:
  • Give sufficient examples of data, and sufficient tests, to test your methods thoroughly.

  • If you find yourself wanting to use a field-of-field, stop. Fill out the template for each method, and figure out another design.

  • Think carefully about how to use dynamic dispatch, and where to define methods, to keep your code as simple and clean as possible.

Note: The following method defined for the class String may be useful:

// does this String come before the given String lexicographically? // produce value < 0 --- if this String comes before that String // produce value zero --- if this String is the same as that String // produce value > 0 --- if this String comes after that String int compareTo(String that)