Chapter 13, Problem 12PE

Program Plan Intro

Creating Polygon

Program plan:

Filename: “Polygon.java”

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

• Define a class “Polygon”.
  • Declare an array list “corners”as class member.
  • Define a constructor “Polygon()”.
    • Initialize the “corners”.
  • Define a method “add()”.
    • Call the method “add()” recursively.
  • Define a method “getArea()”.
    • If the size of the array list is less than 3,
      • Return “0”.
        • Get the corner points.
        • Get the points.
        • Calculate the area.
        • Create an object “remainder” of class “Polygon”.
        • Iterate a “for” loop,
        • • Call the method “add()”.
        • Call the method “add()”.
        • Return the area.

Filename: “PolygonDemo.java”

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

• Import the required packages.
• Define a class “PolygonDemo”.
  • Define a method “main()”.
    • Create the object “p” of class “Polygon”.
    • Call the method “add()” to add the points.
    • Print the area using the method “getArea()”.
    • Print the expected area.
    • Iterate a for loop,
      • Call the method “add()”.
    • Print the area.
    • Print the expected result.