COP2250 Assignment 4

Due Wednesday, 6/4 at 6 am.

If you did not do Assignment 3, then create a NetBeans project that will contain all of your homework projects for the rest of the course: Project for Assignments.

Create a package for chapter 6 and create three different main classes in it; one for each part of the assignment.

• Letters main class
• Calculations main class
• Square Root main class

Import each of your main classes into the Menu class. This is the class that is in the username package of your assignment project.

Assignment Menu

Modify the menu in the main method of the Menu class (or create it if you did not do Assignment 3).

• Display a menu to the user, using a JOptionPane dialog.
  • The choices from Assignment 3 should still be in the menu.
  • Add new options for the programs in this assignment.
  • Add an option for 0 that will allow the user to exit the program.
• The user will enter a number from 0 through 7. Depending on the number that is entered, call the main method from one of the main classes that you have created in the chapter 5 package and the chapter 6 package.
  • Use a switch statement to decipher the user input and call the appropriate main method.
  • For example, if the user selects 1, then call Batting.main(args);
  • If the user enters a number that is not in the menu, then print an appropriate message. DO NOT EXIT THE PROGRAM.
  • Add a sentinel loop to the menu.
    • After the switch statement, use a JOptionPane to show the menu again and read a new selection from the user.
    • Keep displaying the menu and executing options until the user enters 0.
    • You may assume that the user will always enter an integer.
  • After the loop has finished, display the total number of valid options that were processed.
  • The very last statement in the main method should be System.exit(0).
• The main method will need to add a throws java.io.FileNotFoundException to its signature.

  public static void main(String[] args) throws java.io.FileNotFoundException {
  
      ...
  
  }
  

Letters

For the main method in the Letters main class, do the following.

• Use a JOptionPane dialog to read a word from the user.
• Use a loop to build a string that contains each character in the word, separated by a space.
• Use a JOptionPane dialog to display the original string and the string that contains its letters, separated by a space.

Calculations

For the main method in the Calculations main class, do the following.

• Use a Scanner to read doubles from a file named "input.txt".
  • Set the working directory in NetBeans to a directory of your choice.
    • Right-click the name of the project
    • Select Properties
    • Select Run
    • Browse to the directory that you want to use for the working directory.
  • Create a file named named "input.txt" in the working directory.
  • Add at least 10 doubles to the file.
• Calculate and display the following:
  • The largest number in the file.
  • The smallest number in the file.
  • The average of all the numbers in the file.
• Test your program with different data.
  • Edit the file and change the numbers to be sure that your program works.
  • I will test your program with several different versions of data.

Square Root

For the main method in the SquareRoot main class, do the following.

• Using a Scanner, read a double that is greater than 10 from the user.  
  • Use an event controlled loop to be sure that the number is greater than 10.
  • Inside the loop, use another loop to be sure that the user always enters a double.
  • Print appropriate error messages when there is invalid input.
• Calculate the result to be the square root of the number.
• Use an event controlled loop to repeatedly take the square root of the result, until the result is less than 10.
• After the loop is done, display the final result and the number of times that the loop was executed.
• The number 10 in this example should be stored as a constant.
• The main method will need to add a throws java.io.FileNotFoundException to its signature.

  public static void main(String[] args) throws java.io.FileNotFoundException {
  
      ...
  
  }
  

Submit Homework

To hand in the assignment, upload the JAR file online: Submitting homework on-line via the Web.

• Upload the file as binary.
• Be sure that the JAR file contains the .java files. Check this page for more information: Submitting JAR Files