CS 1401 Assignment #4

Date Assigned: Monday, February 12 or Tuesday, February 13, 2007.

Due Date: Monday, February 19, or Tuesday, February 20, 2007, before the beginning of your lab section.

Objective: The main objective of this assignment is to practice using conditional statements.

Programming assignment: use JOptionPane to design a simple calculator. This calculator should read simple expressions describing operations on positive integers, like 15+5 or 3*41, and generate the result of the corresponding arithmetic operation (or an error message if the user accidentally types in something like 1/0). For simplicity, feel free to assume that the expressions do not have blank spaces (but please inform the user about this restriction in the input prompt).

Hints: You already know all the tricks that you need to build such a calculator:

you know how to set up an input message box and how to read from such box -- we had that in Programming Assignment 3;
you know how to check whether a given string contains a given symbol such as +, -, *, or / -- we had that in class; specifically, if the string contains the symbol, the corresponding operation returns the location of this symbol, otherwise it returns -1;
you know how to separate a part of the string before the symbol and a part after the symbol;
you know how to translate strings into integers -- we learned that when we learned how to read an integer from the GUI;
you know how to implement arithmetic operations with integers;
you know how to return the result -- and, if necessary, how to set up an error message box.

All you have to do is add if-then statements to this set-up.

Homework assignment: on a separate sheet of paper, solve Ex. 10 from p. 218 and Ex. 12 from p. 219.

Deliverables: as instructed by your TA.