Chapter 13, Problem 15PE

Program Plan Intro

Generating the subsets of a string

Program plan:

Filename: “SubsetGenerator.java”

This program file is used to define a class “SubsetGenerator”. In the code,

• Import the required packages.
• Define a class “SubsetGenerator”.
  • Declare an string class member “word”.
  • Define a constructor “SubsetGenerator()”.
    • Initialize the “word”.
  • Define a method “getSubsets()”.
    • Create an array list “result”.
    • If the length of the word is “0”,
    • Call “add()” to add the “word” to “result”.
    • Return the “result”.
    • Create a string variable “shorterWord” to hold a substring.
    • Create all the subsets of “shorterWord”.
    • Iterate a “for” loop,
      • Add removed letter “s” to “result”.
      • Add all words without the removed character “s” to “result”.
  • Return the result.

Filename: “SubsetGeneratorDemo.java”

This program file is used to define a class “SubsetGeneratorDemo” to test the class “SubsetGenerator”. In the code,

• Define a class “SubsetGeneratorDemo”.
  • Define a method “main()”.
    • Create the object “generator” of class “SubsetGenerator” to initialize the class member of “SubsetGenerator” as “rum”.
    • Create an array list “subsets”.
    • Call the method “sort()” to sort the array list “subsets”.
    • Print the values in “subsets”.
    • Print the expected values.
    • Initialize the class member of “SubsetGenerator” as “boy”.
    • Set the values of “subsets”.
    • Call the method “sort()” to sort the elements in the array list “subsets”.
    • Print the values of “subsets”.
    • Print the expected value.
    • Initialize the class member of “SubsetGenerator” as “girl”.
    • Set the values of “subsets”.
    • Call the method “sort()” to sort the elements in the array list “subsets”.
    • Print the values of “subsets”.
    • Print the expected value.