Seng2200 Assignment 1-circular double linked list Solved

This assignment aims to build the understanding of Java programming in topics of class, inheritance, interface and circular doubly-linked data structure. A successful outcome should be able to demonstrate a solution of the assignment tasks with valid Java implementation and report.

2. Problem Statement

You are to write a program for a Stock and Station Agent based in Denman, NSW. Your program will be used to compare different land parcels for their value and how appropriate they are for particular types of agriculture as well as soil conservation and possible pasture improvement. Unfortunately, this firm, while willing to trust your programming expertise, finds software development very confronting, and so does not trust things like standard libraries for data structures.

Consequently, all linked list structures to be used are to be designed and coded from scratch and may not use generics or libraries. You need to write your own non-generic version of the Comparable<T> interface; unless you would like to use the following:

public interface ComparePoly {

boolean ComesBefore(Object o); // true if this < param }

You may use the Java standard Scanner library (and associated) for input. 2.1 Written Report

As you design, write and test your solution, you are to keep track of and report (max. 3 pages) on the following:

1. Keep track of how much time you spend designing, coding and correcting errors, and how many errors you need to correct.
2. Keep a log of what proportion of your errors come from design errors and what proportion from coding/implementation errors.
3. Given what we have covered in Topic 3 (Inheritance), how could you treat Rectangles and Squares as special cases of this assignment?

2.2 Point Class

Design and write a Point class. The Point class simply has two double-precision floating point values for x and y coordinate values. It has a method that will calculate the distance of the point from the origin. Your Point class should also contain a toString( ) method

which will allow the conversion of a Point object into a String of the form (x , y) – include the open and close parentheses and the comma in the String. Note that toString() method (throughout this assignment) should return a string rather than print it out. The x and y values will appear in the string formatted according to the 3.2f specification. The string returned, will be used for the output of your results.

2.3 Polygon Class

Design and write a Polygon class which contains a sequence of Point objects representing the ordered vertices of the polygon. Your Polygon class should contain a toString( ) method which will allow the conversion of a Polygon object into a String of the form

[point0point1…pointn-2]: area

For the area values, the format to be used is 5.2f. This will be used for output of your results. The Polygon class has a method that will calculate the area of the polygon, given by the formula in Section 3.

You will also need a method to return the distance from the origin of the pointi vertex which is closest to the origin. Polygon will implement a ComparePoly interface as per the above, and the Polygon comparison specification given below.

For any two polygons, if their area difference is within 0.05% of the smaller polygon, then they are assumed to have equal area. In these cases of equal areas, the polygon with the lower minimum vertex distance from the origin, takes precedence (comes first in your list – Section 2.4).

2.4 Data Structure

You are required to implement a circular doubly-linked list data structure with the class name of MyPolygons, using a single sentinel node to mark the start/finish of what will become a container for Polygon objects. The MyPolygons class must provide distinct methods to

• prependitemsintothestartofthelist(currentitemisthenewfirstinlist),
• append items into the end of the list (current item is the first in list),
• insertbeforeaspecified(current)item,
• step to the next item (making it the current item),
• resetthecurrentitemvariabletothestartofyourlist,and,
• take (then remove) an item from the head of the list.
  Note: that you may not have to use all the above methods in this assignment.

  2.5 Required Processing

  • Read polygon specifications (until end of file, from standard input) and place them into an instance of your container, in input order.
  • Parse and store each polygon specification. A polygon will be specified in the input by the letter P, followed by the number of sides the polygon has (ie: n-1 in the formula above), and then pairs of numbers which represent the respective vertices on the Cartesian plane (x-value then y-value), which means vertices point0 to pointn-2 from the above formula. You do not have to worry about any of the data being missing, or out of order. (Hint: it will be best for your polygon objects to have an array that will contain all n points, that is, explicitly including the last vertex as a

copy of the first, as this will allow the easiest implementation of the area formula, but

you may use an alternate means of storing the polygon vertices if you wish.)

• Then, you are to produce a second list, which contains the same set of Polygon objects, but this time, sorted into decreasing area order. Implement an insert in order

  method to sort the polygon objects as they’re added to the list.

• Output for your assignment is a complete print of both your lists, ie: the polygons in

  input order, and then the polygons in sorted order, listing the area of each polygon in each case, as per the Polygon specification of toString( )given above.

  2.5 Input and Output

  All input (coming from standard input) of polygons will be from a user-defined text file. That is, your program should be able to read polygons from a text file. A sample test file is as follows (you should create one for self-testing before submission):

  All output is to the standard output. A sample output of the above input is as follows:

P 6 4 0 4 8 78 7 3 9 0 7 1 P 3 4.1 0.0 4.0 8.2 7.3 8.4 P 5 4.0 0 4 8.1 7.2 8 7 3 9 0

You may only use Java libraries for input and output (therefore you may use Scanner and

the associated libraries for input), and for calculating the distance to origin (therefore you

may use the Math sqrt() method). Current University Lab Environment is Java 11.0

3. Polygon Area Calculation12 𝑛−2
The area of a polygon, specified on the Cartesian plane by its vertices, is given as follows:

𝐴 = ��(𝑥𝑖+1 + 𝑥𝑖)(𝑦𝑖+1 − 𝑦𝑖)� 𝑖=0

Note: that for a seven-sided figure, such as the one shown, 𝑛 = 8, because the last point describing the polygon is equal to the first (it is always the same Cartesian point).

You may verify your polygon formula implementation using

• https://rechneronline.de/pi/simple-polygon.php 4. Submission

Submission is through the Assessment tab for SENG2200 on Blackboard under the entry Assignment 1. If you submit more than once then only the latest will be graded. Every submission should be ONE ZIP file (not a .rar, or .7z, or etc) named c9999999.zip (where c9999999 is your student number) containing:

• Assessment item cover sheet. (No longer Required)
• Report (PDF file): addresses the tasks in Section 2.1.
• Program source files (each Class in a separate .java file)

  Programming is in Java. Name your startup class PA1 (capital-P capital-A number-1), that is, the marker will compile your program with the command:

       javac PA1.java
  

  …and to run your program with the command:

       java PA1 test.dat
  

  …within a Command Prompt window.

  Note that test.dat is a placeholder; your program will have to handle different names and extensions for testing.

  If your program cannot be compiled and executed (incl. run-time errors) by using the above commands, you may receive ZERO marks without being examined.