KIT107 Programming                                                                                2022

Assignment 1

QQ1703105484

Due Date

This assignment is to be completed in pairs. The assignment is due at 3PM Wednesday August 10th 2022 and should be completed with a partner. You and your partner should work together on all of the design and programming. It should be done using the pair- programming methodology and not by division of labour. Use the “Assignment 1 Pairs” groups on MyLO to find and register your pair:

• if you already have a partner — start at the bottom of the list of pairs and when you find an empty group, both you and your partner should enrol in that group.
• if you do not have a partner — start at the top of the list of pairs and when you find a group with 0 or 1 member(s), add yourself to that group. If you are the second person to join, you now have a partner and so email your partner to get started.

Background

The belligerent country of Kablamistan has launched an inter-continental ballistic missile towards a country 8000km away which threatens to destroy the peaceful Goners who live there.

Fortunately the United Nations has anticipated this possibility and, out of concern for the citizens of Goneria, has placed a high-powered laser at the midpoint between the site of the missile’s launch (Launchtown, Kablamistan) and the target (Doomsville, Goneria). The laser is capable of destroying the missile in mid-air — even at its highest point of 20km above the Earth.

Unfortunately the laser’s guidance system got fried when the soldier monitoring the system blew its fuse when trying to cook a pop-tart with the laser and no replacement component could be found. Given the military’s well known policy of awarding contracts to the lowest bidder, you’ve been given the job of developing software to upload into the 80286 computer that will be used to drive the laser! For free!

Also unfortunately, the missile is shielded against lasers and will need to be hit multiple times before being destroyed.

Doomsville (Goneria)

Launchtown (Kablamistan)

The technical specifications are as follows:

• The missile
  • is fired towards Doomsville at 12:30PM, i.e. at lunchtime in Launchtown!
  • flies an elliptical path (with a major radius of 4000km and a minor radius of 20km) which is 7998km long. And
  • travels each of the 180 x 1° segments in which it can be targeted by the laser in 7.405s.
• The laser
  • is 4000km between Launchtown and Doomsville directly below the path of the missile;
  • requires 15.737s to charge before it may be fired;
  • moves in 1° increments — where 0° is along the ground to Launchtown, 90° is straight up, and 180° is along the ground to Doomsville;
  • requires 3.61s to move 1° (and starts perpendicular to the ground, i.e. at 90°);
  • should only be fired at degrees in the range 1–179°;
  • may move while being charged; and
  • fires instantly for an infinite distance.

Given an angle t in the range of 0–180° for the direction of the laser, the position of the missile on its elliptical path is the coordinate (x,y) where x=4000*Math.cos(r) and y=20*Math.sin(r). r is the value t converted to radians and the conversion can be done with a built-in method: r=Math.toRadians(t);

If the missile will be at this coordinate at the time the laser is aiming there then this is a firing solution. Firing solutions consist of:

• the time the laser should be fired;
• the degree at which the laser should be aimed; and
• the resulting coordinate at which impact with the missile would occur.

Program specification

You and your partner must write a Java program to calculate and display all possible firing solutions. These should be found from the greatest distance from Doomsville to the least distance from Doomsville with the previous firing solution as the starting point for the next.

Your solution should comprise the following files:

• TimeInterface.java and Time.java — the Time ADT as used in lectures and tutorials, extended with a method to add seconds to an existing time. The heading for this additional function should be:

void addSeconds(double s);

Only the whole number portion of the double value should be added to the time object;

• FiringSolutionInterface.java and FiringSolution.java — the specification and implementation (respectively) of a firing solution. A firing solution should be implemented as a class with instance variables which consist of:
  • the time the laser should be fired (as a Time value);
  • the degree at which the laser should be aimed (as an int); and

• • the resulting coordinate at which impact with the missile would occur (as two

double fields, x and y).

and the operations should include a getter and setter for each field; and

• AssigOne222.java — the file which contains the main() method and other functions which implement the required task. (There is no need to sub-divide main() into additional methods.)

A starting point is available on MyLO for you to download. You should complete all the required files. You may need nextLine() and nextInt() from java.util.Scanner, print() and println() from java.lang.System, compareTo() and charAt() from java.lang.String, valueOf() from java.lang.Integer, and format() from java.text.DecimalFormat. You will also need to use if and if-else statements, and for and while loops.

An example of the program’s output is shown below:

At time 12:39:37 PM, fire at 78 degrees to impact missile at (831.647, 19.563) At time 12:39:59 PM, fire at 81 degrees to impact missile at (625.738, 19.754) At time 12:40:22 PM, fire at 84 degrees to impact missile at (418.114, 19.890) At time 12:40:44 PM, fire at 87 degrees to impact missile at (209.344, 19.973) At time 12:41:06 PM, fire at 90 degrees to impact missile at (0.000, 20.000)

At time 12:41:28 PM, fire at 93 degrees to impact missile at (-209.344, 19.973) At time 12:41:50 PM, fire at 96 degrees to impact missile at (-418.114, 19.890) At time 12:42:13 PM, fire at 99 degrees to impact missile at (-625.738, 19.754) At time 12:42:35 PM, fire at 102 degrees to impact missile at (-831.647, 19.563)

At time 12:48:52 PM, fire at 153 degrees to impact missile at (-3564.026, 9.080) At time 12:49:15 PM, fire at 156 degrees to impact missile at (-3654.182, 8.135) At time 12:49:37 PM, fire at 159 degrees to impact missile at (-3734.322, 7.167) At time 12:49:59 PM, fire at 162 degrees to impact missile at (-3804.226, 6.180) At time 12:50:21 PM, fire at 165 degrees to impact missile at (-3863.703, 5.176) At time 12:50:44 PM, fire at 168 degrees to impact missile at (-3912.590, 4.158) At time 12:51:06 PM, fire at 171 degrees to impact missile at (-3950.753, 3.129) At time 12:51:28 PM, fire at 174 degrees to impact missile at (-3978.088, 2.091) At time 12:51:50 PM, fire at 177 degrees to impact missile at (-3994.518, 1.047)

Algorithm

AssigOne222.java could implement the following algorithm:

• setting up the launch time
• iterating through each position (degree) of the missile from Launchtown to Doomsville and for each
  • repeating the following steps until a solution is found or it is determined there are no solutions
    • calculating how the laser would need to move to get there
    • calculating how the missile would need to move to get there
    • determining how many seconds the movement of each item would take and, if the laser can get there no later than the missile
      • determine the (x,y) coordinate of impact and the time
      • create a firing solution of these values
      • display the time and firing solution (you can make use of the defined DecimalFormat objects to format the output of Time and FiringSolution objects)
    • otherwise
      • moving the missile to the next location (degree)

Program Style

Your program should follow the following coding conventions:

• final variable identifiers should be used as much as possible, should be written all in upper case and should be declared before all other variables
• variable identifiers should start with a lower case letter
• every if and if-else statement should have a block of code (i.e. collections of lines surrounded by { and }) for both the if part and the else part (if used)
• every do, for, and while loop should have a block of code (i.e. {}s)
• the keyword continue should not be used
• the keyword break should only be used as part of a switch statement
• opening and closing braces of a block should be aligned
• all code within a block should be aligned and indented 1 tab stop (or 4 spaces) from the braces marking this block
• instance variables should be used sparingly with parameter lists used to pass information in and out of functions
• local variables (excluding loop counters) should only be declared at the beginning of methods (either as parameters or otherwise)
• commenting:
  • There should be a block of header comment which includes at least
    • file name

• • • student names
    • student identity numbers
    • a statement of the purpose of the program
    • date
    • the percentage of the work completed by the authors — 50:50 is expected and assumed but reasons should be given if it is more/less than this
  • Each variable declaration should be on a single line and should be commented
  • There should be comments that identify groups of statements that do various parts of the task
  • Comments should describe the strategy of the code and should not simply translate the Java into English

Marking scheme

What and how to submit

What to submit

• You should submit the three source files (Time.java, FiringSolution.java, and AssigOne222.java) file. That is all that is required. Do not submit a RAR file — it will not be marked.

How to submit

• Log in to MyLO and navigate to the Assignments tool under the Assessments

menu in the top tool bar.

• Select Assignment 1 from the list of available drop-boxes.