CS 1401 Assignment #4

Date Assigned: Monday, February 11, or Tuesday, February 12, 2008.

Due Date: Monday, February 18, or Tuesday, February 19, 2008, 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 English language sentence generator with a random component, so that the user never knows quite what to expect for the output sentence, unless one “special” name is entered. This sentence generator should read expressions composed of a person’s name followed by a positive integer between 1 and 9999 enclosed in parentheses, such Cupid(1442). For output, it should produce a complete sentence about the person, such as “Cupid is a great Java programmer!” The procedure for completing the sentence is as follows:

· The program should pass the input integer as a “seed” to a pseudo-random number generator object (see below).

· The random number generator will use the seed to produce a single-digit integer between 0 and 9 as output.

· Write your program so that the sentence completion is based upon the output random integer, or a match with the “special” name.

· To reduce the number of sentences that you have to code, you may use one sentence completion for multiple random integers or “special” name match, as shown in the examples below:

Random number is 0, 1, or 2: “ is new to Java, and so his code is sometimes off target.”

Random number is 3, 4, or 5: “ is right on the mark with his Java conditional statements.”

Random number is 6, 7, or 8: “ really knows how to pair up a great algorithm with great code!”

Input name matches defined “special” name, or random number is 9: “, you’re the best!”

Hints: You already know most of the tricks that you need to build such a sentence generator:

• You know how to set up an input message box and how to read from such box – that was in Programming Assignment 3.
• You know how to check whether a specific character or substring, such as ‘(‘ , is found in a string; if it is found, the location will returned, so that you will know the input is in the correct format and that the name of the person occurs before that location.
• You know how to specify substrings after a given location and before the final parenthesis.
• You know how to translate strings into integer numbers -- you learned that when you learned how to read a number from the GUI.
• You know how to display the result -- and, if necessary, how to set up an error message box.

To Add: For this lab add the following new concepts:

• Use an if-then statement to check that ‘(‘ has been entered as required for input. Continue processing the input if it is found; otherwise, display an error message box.
• Define a Boolean variable to indicate whether or not the name provided as input is the same as the name you have defined as “special.” You will need to compare the two strings to decide this. If the name matches the “special” name, there is no need to compute a random number; just go right to the sentence completion part. If the name does not match, compute the random number using the number entered in parentheses as the seed.
• Add this import statement at the top of your program, in addition to the one for swing:

import java.util.Random;

· Add these statements to your code to create a new pseudo-random number generator object, using class Random:

Random rand = new Random(number); //number should be assigned the input integer value

randNum = rand.nextInt(9); //.nextInt(9) will return an integer from 0-9

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.

Extra Credit: In addition to this assignment, write the program using a switch statement rather than if-else statements for the sentence completions, and add a check for valid input integers between 1 and 9999. Display an error message if the input number is out of range.