COMP 110-003 Fall 2008

Description

Write a GUI-based program that mimics a calculator. The program should take as input two floating-point numbers and the operation to be performed. It should then output the numbers, the operator, and the result.

The user input should be in the format operand1 operator operand2, where the operands and the operator are separated by single spaces. For example, to add 2 and 3, the user should enter 2 + 3 in the text field of the dialog box.

You should support the following operations: addition (+), subtraction (-), multiplication (*), division (/), and mod (%).

Special cases to handle:

• Since the user will enter floating-point numbers, you will have to convert the numbers to integers when performing modular arithmetic. (Note: it is legal to use the % operator with floating-point numbers in Java, but for this assignment, assume that it can only be used with integers.)
• You can assume that the user will always enter numbers as operands. You are not responsible for making sure that the user enters numbers, instead of letters, for the operands. This would cause a "NumberFormatException" when trying to parse the input string.

Here's an example run:

Here are a few tips for this program.

Note: You may ONLY use the String methods listed on pp. 80-82 (4th edition) or p. 78 (5th edition) for this assignment. In other words, you may not use other available Java libraries or methods for parsing strings.

Extra Credit:

• (5 points) Add the ^ operator to your code. There are Java packages that include the ^ operator, but you cannot use them for this extra credit. When testing the ^ operator use small numbers! Note: operand1 ^ operand2 means that operand1 should be raised to the operand2(th) power. Assume that operand2 is an integer.
• (3 points) If the user attempts to divide by 0, print an error message (e.g. "Division by 0 not allowed")
• (2 points) If the user enters an invalid operator, print an error message (e.g. "Unsupported operator").

• Name your class Calculator and your Java source file Calculator.java.
• Make sure you put the standard program header at the top of your code.
• Follow the instructions for creating a JAR file named yourlastname_prg2.jar containing your Java source code.
• Send me an email with the subject line

  COMP110 Program2 yourlastname

  with the following attachments:

  • yourlastname_prg2.jar (where yourlastname is your last name), which includes your Calculator.java source file
  • yourlastname_prg2.txt (or .doc), which has a short write-up of questions you had and/or problems you encountered while doing this assignment (make sure to include the standard writing assignment header)

• Print a copy of your code (Calculator.java) and hand it in at the beginning of class on the due date.

When I run/examine your program, it must satisfy the following requirements. The maximum point value for each is shown in brackets.

1. [3] Your class, Java source file, and Jar file must be appropriately named (as specified above).
2. [2] Pledge header
3. [5] Your printed copy of the code (Calculator.java) must be handed in.
4. [15] You must use the JOptionPane class to create dialog boxes for user input and output (see Lab 2). Your user input dialog box should contain instructions for using the program, including a list of the supported operations.
5. [15] You must correctly parse the user input String.
6. [15] You must display the correct result of the calculation to the user.
7. [10] You must convert floating-point numbers to integers to perform modular arithmetic.
8. [5] You must use meaningful variable names, which conform to the style guidelines and Java naming conventions discussed in class.
9. [5] You must comment your code, including block-like multi-line comments and single-line comments where appropriate. In addition, your code must be neatly and clearly formatted using appropriate "white space."
10. [10] Extra Credit.

• If your program does not compile or run (i.e., has a syntax error), you will receive 0 credit for the items listed above in bold (so, at most 15/75 points).
• Remember that an implicit requirement for all assignments is that your code must include (at the top) the standard program header with pledge.