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
equires 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 SyntaxE
or should
e 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 e
or 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
. 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 Ru
ic
Criteria Meets Does Not Meet
Design
20 points 0 points
GUI is hand coded and matches
equired 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
Co
ectly converts prefix to postfix (20) Does not co
ectly convert prefix to
postfix (0)
Co
ectly converts postfix to prefix (20) Does not co
ectly convert postfix to
prefix (0)
Co
ectly parses expressions without
space delimiters (10)
Does not co
ectly parse expressions
without space delimiters (0)
SyntaxE
or exception is thrown on
expression with invalid syntax (5)
SyntaxE
or exception is not thrown on
expression with invalid syntax (0)
SyntaxE
or is caught and a
JOptionPane message is displayed (5)
SyntaxE
or 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
esult in a non-empty stack (0)
Documentation
10 points 0 points
Co
ect UML diagram included (3) Co
ect 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)