CMSC350 Project 2 Solution

1. Specification
Design, write and test a program that accepts an arithmetic expression of unsigned integers in postfix notation in which the tokens are separated by spaces and builds and processes the arithmetic expression tree that represents that expression.

The main class will be P2GUI. It should create a Swing based GUI shown below:

Pressing the Construct Tree button should cause the following: (i) the arithmetic expression tree that represents the entered postfix expression will be constructed, (ii) using that tree, the corresponding fully parenthesized infix expression should be generated and displayed in the GUI and finally (iii) a file should be generated that contains the 3-address format instructions corresponding to the arithmetic expression. These topics, including relevant classes for implementing and processing an expression tree, are discussed in the week 4 reading “Binary Trees, Expression Trees, BST (AVL) trees, and B-Trees” section II “Expression Trees”.

The above example should produce the following output file containing the 3-address instructions:

Add R0 5 9
Sub R1 3 R0
Mul R2 2 3
Div R3 R1 R2

It is not necessary to reuse registers within an expression as shown in the above mentioned reading and you can assume there are as many available as needed. Each new expression should, however, begin using registers starting at R0.

operands such as 2a, which are not valid integers. If an invalid token is detected, a checked custom exception InvalidTokenException should be thrown and caught by the main class and an appropriate error message should be displayed. Below is an example:

Your program should compile without errors.


In addition the following design constraints should be followed: declare all instance variables private; avoid the duplication of code.

2. Submission requirements


2. The solution description document P2SolutionDescription (.pdf or .doc / .docx) containing the following:
(1) Assumptions, main design decisions, error handling;
(2) A UML class diagram that includes all classes you wrote. Do not include predefined classes. You need only include the class name for each individual class, not the variables or methods;
(3) A table of test cases including the test cases that you have created to test the program. The table should have 5 columns indicating (i) what aspect is tested, (ii) the input values, (iii) the expected output, (iv) the actual output and (v) if the test case passed or failed. Each test case will be defined in a table row.
(4) Relevant screenshots of program execution;
(5) Lessons learned from the project;



Grading Rubric:

Criteria Meets Does Not Meet

Design 5 points 0 points

GUI is hand coded and matches required design GUI is generated by a GUI generator or does not match required design
Other classes are used to support the implementation of the arithmetic expression tree Does not use other classes to support the implementation of the arithmetic expression tree
All instance data is private Some instance data is not private
Uses good object-oriented design practice regarding code efficiency, encapsulation and information hiding, class and code reuse, high cohesion of classes, avoiding code duplication. Does not use good object-oriented design practice regarding code efficiency, encapsulation and information hiding, class and code reuse, high cohesion of classes, avoiding code duplication.





Functionality 10 points 0 points

Produces correct fully parenthesized infix expressions for all input Does not produce correct fully parenthesized infix expressions for some input
Produces correct three address file for all input Does not produce correct three address file for some input
Correctly parses expressions with space delimiters Does not correctly parse expressions with space delimiters
Registers restart at R0 on each new expression Registers do not restart at R0 on each new expression
Detects and handles invalid tokens Does not detect and handle invalid tokens

Test Cases 5 points 0 points

Test cases table is defined and included in the P2SolutionDescription document Test cases table is not defined and
included in the P2SolutionDescription document
All operators included in test cases Some operators not included in test cases
Test cases include expressions with and without spaces Test cases don't include expressions with and without spaces
Test cases include a case to test invalid token beginning with a digit Test cases do not include a case to test invalid token beginning with a digit
Test cases include a case to test invalid operators Test cases do not include a case to test invalid operators



Documentation 5 points 0 points

Solution description document P2SolutionDescription includes all the required sections (appropriate titled). No solution description document is included
Source code follows Google recommendation Java style Source code does not follow Google recommendation Java style
Comment blocks with class description included with each class Comment blocks with class description not included with each class
Source code is commented and indented Source code is not commented and indented

Overall Score Meets Does not meet
16 or more 15 or less