CMIS 350

CMSC 350 Project 1

The first programming project involves writing a program that converts prefix expressions to postfix and postfix

expressions to prefix. Customary infix expression place the operator between the two operands. In a prefix

expression, the operator comes before the two operands. In a postfix expression it comes after them. One benefit of

prefix and postfix expressions is that they never require parentheses nor rules regarding precedence or associativity.

The program for this project should consist of three classes. The main class should create a GUI that allows the user

to input an expression in either prefix or postfix and convert it to postfix or prefix, respectively. The GUI should look

as follows:

The GUI must be generated by code that you write. You may not use a drag-and-drop GUI generator.

The second class should contain the code to perform the conversions. The pseudocode for prefix to postfix, which

requires two stacks, is shown below:

tokenize the string containing the prefix expression

while there are more tokens

push the token onto a reversal stack if it is not a space

while the reversal stack is not empty

pop the next token from the reversal stack

if it is an operand

push it onto the operand stack

else it is an operator

pop two operands off of the operand stack

create a string with the two operands followed

the operator

push that string onto the operand stack

pop the postfix expression off the stack

The pseudocode for the postfix to prefix conversion, which requires only one stack, is shown below:

tokenize the string containing the postfix expression

while there are more tokens

get the next token

if it is a space

skip it

else if it is an operand

push it onto the operand stack

else it is an operator

pop two operands off of the operand stack

create a string with the operator followed by

two operands

push that string onto the operand stack

pop the prefix expression off the stack

Be sure to add any additional methods needed to eliminate any duplication of code.

The input expressions should not be required to contain spaces between tokens unless they are consecutive operands.

The output expressions should always have a space between all symbols. A checked exception SyntaxError should

be thrown by the methods that perform the conversions if an empty stack is ever popped or the stack is not empty

once the conversion is complete. That exception should be caught in the main class, where a JOptionPane window

should be displayed containing an error message.

You are to submit two files.

1. The first is a .zip file that contains all the source code for the project. The .zip file should contain only

source code and nothing else, which means only the .java files. If you elect to use a package the .java

files should be in a folder whose name is the package name. Every outer class should be in a separate .java

file with the same name as the class name. Each file should include a comment block at the top containing

your name, the project name, the date, and a short description of the class contained in that file.

2. The second is a Word document (PDF or RTF is also acceptable) that contains the documentation for the

project, which should include the following:

a. 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

b. A test plan that includes test cases that you have created indicating what aspects of the program each

one is testing

c. A short paragraph on lessons learned from the project

Grading Rubric

Criteria Meets Does Not Meet

Design

20 points 0 points

GUI is hand coded and matches required design (4)

GUI is generated by a GUI generator or does not match required design (0)

Supplied algorithm is used (5) Supplied algorithm is not used (0)

Code duplication is eliminated (3) Contains duplicated code (0)

Contains separate class for expression conversion (4)

Does not contain separate class for expression conversion (0)

Contains checked exception class (4) Does not contain checked exception class (0)

Functionality

60 points 0 points

Correctly converts prefix to postfix (20) Does not correctly convert prefix to postfix (0)

Correctly converts postfix to prefix (20) Does not correctly convert postfix to prefix (0)

Correctly parses expressions without space delimiters (10)

Does not correctly parse expressions without space delimiters (0)

SyntaxError exception is thrown on expression with invalid syntax (5)

SyntaxError exception is not thrown on expression with invalid syntax (0)

SyntaxError is caught and a JOptionPane message is displayed (5)

SyntaxError is not caught or a JOptionPane message is not displayed (0)

Test Plan

10 points 0 points

All operators included in test cases (3) Some operators not included in test cases (0)

Test cases include expressions without spaces (3)

Test cases don't include expressions without spaces (0)

Test cases include cases that pop an empty stack (2)

Test cases do not include cases that pop an empty stack (0)

Test cases include cases which result in a non-empty stack (2)

Test cases do not include cases which result in a non-empty stack (0)

Documentation

10 points 0 points

Correct UML diagram included (3) Correct UML diagram not included (0)

Lessons learned included (4) Lessons learned not included (0)

Comment blocks included with each Java file (3)

Comment blocks not included with each Java file(0)