Exercise #1

Overview

This repo contains the following .java files:

• Ex1 - most of the functions were written by me (the rest were provided to us.)
• Ex1Test - I added my own JUnit tests to all the functions (the preexisting tests were unchanged.)
• Ex1_GUI - GUI provided to us (unchanged.)
• StdDraw - drawing library provided to us (unchanged.)

It also contains:

• PseudoCode.txt - pseudocode for the functions I wrote.
• output.png - a screenshot of the output (see below.)

Warning

The pseudocode does not fully reflect the final implementation.

Execution

To run the project, run (from I2CS_Ex1/src/):

javac Ex1.java Ex1_GUI.java StdDraw.java
java Ex1_GUI

Note

I haven't downloaded the JUnit jar, so I've only run Ex1Test.java directly from my IDE.

Output

The following is a screenshot of the output of Ex1_GUI:

TODO:

• Write pseudocode for all the functions
• Implement tests for all functions
• Actually write the code
• Write documentation
• Write README
• Add screenshot

Personal notes

In the previous assignment, I included my pseudocode inside the function bodies. This time, I've written it in a separate file.

I wrote my (initial) tests BEFORE implementing the code. This was a new, yet fruitful experience. I also tried to add some edge cases to the test suite.

Note

I prefer the style of "early returns" (as I find it easier to read than nesting.)

Explanations

The following functions are a little complicated. The general idea is:

poly()

array -> String

1. Ensure the polynomial has coefficients
2. Create an array with {sign, where appropriate}{coefficient}
3. Append {x}{power} to each element, where appropriate
4. Convert the array to a string
5. Handle edge cases (empty string, leading +)
6. Return string

getPolynomFromString()

String -> array

1. Split the polynomial into an array (using space as the delimiter)
2. Ensure even the first element has a leading sign
3. Find the highest power and create an appropriate array
4. Loop through the array of strings
   • If there's a power (the string includes a caret), insert the coefficient into that position of the array
   • If it's just an x term, insert to the 1st position
   • If it's a constant term, insert to the 0th position
5. Return array