README.md

Assignment 1: Train to Javari Park

CSGE601021 Programming Foundations 2 @ Faculty of Computer Science Universitas Indonesia, Term 2 2017/2018

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This document contains the description and general information required for completing the first assignment of Programming Foundations 2 course. The assignment is about creating a program for a (imaginary) train station manager that helps local people to send endangered cat species to Javari Park conservation zoo.

This assignment covers programming topics as follows:

• Basic I/O processing, specifically handling standard input and standard output
• Conditional and iteration constructs
• Recursion
• Basic OO programming in Java, specifically implementing simple data classes with public attributes and methods

Table of Contents

1. Background
2. Description
3. Preparation
4. Running & Testing
5. Submission
6. Checklists

Background

Welcome to Javari Park conservation zoo!

The wild cat pictured above is one of the famous Tomcat that lives in Javari Park. Usually they hang around with another wild cat named Servlet and together they can create Web-based applications. Pretty cool, right?

It is not rare to find cats, or other animals, that can code in Javari Park. One kind of snake named Python is also able to create Web application by flipping Flask or reading incantation from a book called Django.

Sadly, it is not the case in the world where you live in. You will not find cats that can code. But in some occasion when the stars and planets are aligned, there is one place named Tamfir where the animals, especially cats, become self-aware and able to write code.

Since it is very rare to have cats that can write code, they need to be preserved and guarded to avoid being poached. In order to do so, the cats will be transported to Javari Park by using a special train. Your tasks as a programmer is to help implementing a train-loading system at Tamfir Train Station that will receive cats and load them into train.

Description

You are asked to develop a Java program named A1Station that will be used to manage train cars and cats that will be loaded into the train. The program uses two classes to represent the concepts involved in the problem. The first class, WildCat, represents the cat that will be transported to Javari Park. The second class, TrainCar, represents the car in a train that may linked to another car in the same train and it will also contain an instance of WildCat.

The starter code is available in src/main/java directory. Please ensure all of your work is stored in the same folder as starter code.

The following subsections describe the specifications of each class.

WildCat Class

The following table-like text is text-based class diagram that models WildCat class:

WildCat
- name : String
- weight : double
- length : double
----------------------------
+ WildCat(name : String,
weight : double,
length : double)
+ computeMassIndex() :
double
----------------------------

The class diagram specifies the following instance variables and methods must exist in WildCat class:

• A variable with type String to store the name of a cat

• A variable with type double to store the weight of a cat in kilograms

• A variable with type double to store the length of a cat in centimeters

• A constructor method that accepts three arguments with following types in order: String, double, double

• A public method named computeMassIndex() that returns a value with type double and computes the Body Mass Index (BMI) based on cat's weight and length

  The formula is as follows: BMI = weight (kg) / length (m) squared

TrainCar Class

The following table-like text is text-based class diagram that models TrainCar class:

TrainCar
- cat : WildCat
- next : TrainCar
-----------------------------
+ TrainCar(cat : WildCat)
+ TrainCar(cat : WildCat,
next : TrainCar)
+ computeTotalWeight() :
double
+ computeTotalMassIndex() :
double
+ printCar() : void
-----------------------------

The class diagram specifies the following instance variables and methods must exist in TrainCar class:

• A variable with type WildCat to store a cat that will be carried by this car

• A variable with type TrainCar to store a reference to the next car in the train

• Two constructor methods: the first constructor accepts a single argument with type WildCat, the latter accepts two arguments with type WildCat and TrainCar

• A public method named computeTotalWeight() with return type double that calculates the total weight of this car and its content plus total weight from subsequent car(s), recursively

• A public method named computeTotalMassIndex() with return type double that calculates the total of body mass index of the cat in this car plus every cat(s) from subsequent car(s), recursively

• A public method name printCar() that displays content of this car and the link to subsequent car if this car is not the last car in the train, recursively

  Specification: If current TrainCar object is not linked to another car (i.e. single car), printCar() must print a string "(<CAT>)" where <CAT> is the name of cat contained in current train. Otherwise, print string "(<CAT>)--".

A1Station Program Class

A1Station program will accept input from standard input (i.e. via keyboard) and display the output to standard output (i.e. command prompt/shell). The first line given from input will be a single integer value, N, that specifies the number of cats that will be processed by the program. The next N lines from the input will contain a string that describes each cats and formatted as follow:

<NAME>,<WEIGHT>,<LENGTH>

When processing each line of input, the program should be able to parse the input and instantiate the object of WildCat class based on parsed information. Then, the cat needs to be inserted into a car. However, the program cannot simply insert the cat into an existing car. If there is an existing car on the track, create a new car to contain the cat and make the new car has link to the most recent car on the track.

# Before
cars on the track: (Car N)--(Car N-1)--...
# After
cars on the track: (Car N+1)--(Car N)--...

If there is no car on the track, then create a new car to contain the cat and assign it to the track as the first car on the track.

# Before
cars on the track: NONE
# After
cars on the track: (Car 1)

Hint: You need to have a variable that keep track the most recent car on the track. The most recent car has the information about the N-th cat and the previous car. The previous car has the information about the N-1-th cat and the previous previous car. And so on.

Hint: Noticed the pattern? In short, a train is defined recursively where a train is either consists of itself (i.e. single car) or followed by another train (car).

After a new car has been added to the track and linked to existing car (if any), you need to check whether the total weight of all cars in the train has exceeded the threshold (i.e. 250 kg). If the total weight has exceeded threshold, then depart the train, empty the track, and keep processing the remaining input. When there is no further input (i.e. has reached the end of input) and there is a train on the track, depart the train immediately.

Whenever a train departed, the program will display the following information:

1. A line of string that says: "The train departs to Javari Park"

2. A line of string that displays cats in the cars as text

   • Format: "[LOCO]<--(Cat in car N)--(Cat in car N-1)--...-(Cat in car 1)"
   • Example 1: "[LOCO]<--(DELTA)--(CHARLIE)--(BOB)--(ALICE)"
   • Example 2: "[LOCO]<--(ALICE)"

   Hint: Remember printCar() method in TrainCar object? You can use it to recursively print each car!

3. Two lines of string that describe statistics about average mass index of all cats in the train

   • First line is a string that says: "Average mass index of all cats: " followed by the actual computed average mass index
   • Second line is a string that says: "In average, the cats in the train are *<CATEGORY>*" where <CATEGORY> has four possible values: underweight if the average mass index is less than 18.5, normal if the average mass index is greater than or equal to 18.5 and less than 25, overweight if the average mass index is greater than or equal to 25 and less than 30, obese if the average mass index is greater than or equal to 30.

   Hint: Similarly, you can use computeTotalMassIndex() method in TrainCar object to get the total mass index.

Preparation

Please follow the instructions in the root (main) README.

Running & Testing

To run the unit tests:

gradle :assignment-1:test

To check for any code style issues in your work:

gradle :assignment-1:checkstyleMain

Tips: You can view the test reports as HTML document. See the generated HTML documents in the subfolders at build/reports folder.

If you want to run the main program via command prompt/terminal, go to src/main/java directory, compile your Java classes, and run the Java program class.

# Windows users: use backward slash as path separators
cd src/main/java
javac *.java
java A1Station.java

You can also try to check your program correctness by comparing output produced by your program with the expected output. The teaching team has provided 5 examples of input and their expected output in testcases directory. You can execute the following command to automatically run your program and feeding it with the input from a file in testcases directory.

# Assuming the current working directory of your terminal is assignment-1
# directory
gradle -q :assignment-1:run < testcases/in1.txt

Submission

Please save & push your latest work (commit) into your online Git repository on GitLab no later than 21:00 at 14/03/2018. Do not forget to invite your TA as a Master of your GitLab project. The teaching team will only grade your work based on the latest commit that has been pushed no later than the specified date & time.

Checklists

Mandatory Tasks Checklist

• Make at least 1 commit that contains your progress in completing assignment 1
• Push your commits to online Git repository at your GitLab project
• Implement WildCat & TrainCar classes correctly
• Implement A1Station program correctly
• Demonstrate your program to your TA

Additional/Bonus Tasks Checklist

• Make sure there are no code style issues in your source code
• Your program can produce functionally correct output when compared to the expected output in testcases directory
• Your program can handle testcase(s) provided by your TA during demo session