Chapter 16, Problem 10PP

Program Plan Intro

A method “length()”

Program plan:

• In a file “LispList.java”, create a class “LispList”,
  • Create an object for “EmptyList”.
  • Declare the method “isEmpty()”.
  • Declare the method “head()”.
  • Declare the method “tail()”.
  • Declare the method “cons()”.
  • Declare the method “length()”.
• In a file “EmptyList.java”, create a class “EmptyList”,
  • Define the default constructor.
  • Define the “cons()” method to return the object of “NonEmptyList”.
  • Define the method “isEmpty()” to returns true.
  • Define the method “length()” that returns “0”.
  • Define the method “head()” that returns an exception “UnsupportedOperationException”.
  • Define the method “tail()” that returns an exception “UnsupportedOperationException”.
  • Define the method “toString()” that returns empty string.
• In a file “NonEmptyList.java”, create a class “NonEmptyList”,
  • Declare the object for “Object” and “LispList”.
  • Define the constructor that assigns the object properties.
  • Define the “cons()” method to return the object of “NonEmptyList”.
  • Define the method “isEmpty()” that returns false.
  • Define the method “length()”,
    • Check whether the list is empty,
      • If it is true, returns “0”.
    • Otherwise, return the update length.
      • • Define the method “head()” that returns the object properties of “Object”.
        • Define the method “tail()” that returns the object properties of “LispList”.
        • Define the method “toString()” that returns the string representation.
• In a file “LispListTest.java”, create a class “LispListTest”,
  • Define the method “main()”,
    • Create an object for “EmptyList”.
    • Print the actual and expected output.
    • Create an object for “NonEmptyList”.
    • Print the actual and expected output.
    • Create another object for “NonEmptyList”.
    • Print the actual and expected output.
    • Assign the value returned from the method “cons()”.
    • Print the actual and expected output.