CS 230 Fall 2009                                                Assignment 6 –Looping (Dreaded Canine Flu Pandemic Silly Simulation)                      

100 Assignment Points

Assigned: 10/12/2009

Due: 10/26/2009 at the start of class (no class on Oct 19 and 20 due to fall break)

Pre-Lab (Do Before Lab):  Bring materials – a way to save a copy for you and a copy to turn in. Read through the whole assignment; hints and details are spelled out throughout. Plan out tasks, objects, and events needed for program.  Think about the main button’s pseudocode / flow chart.

Main Assignment Description:

You are creating an extremely simplified simulation. Write a program that simulates the spread of the newly discovered and dreaded Canine Flu,  which has no known vaccine against it. Get from the user the starting number of people with the flu, severity level of the outbreak (1-10), and the number of weeks to simulate. Display in a RichTextBox for each week elapsed, the number of weeks elapsed to that point and the number of people that are infected. After the given number of weeks, display in labels or read-only textboxes the final number of currently infected people. NOTE – this task MUST be done with a loop – I need to see the week by week results in the rich text box – and in order to see that, you cannot do a single one-time calculation. 

· Provide capabilities to simulate, clear (the inputs and outputs) to start again, and to exit.

Please set the name of the project to something other than the default name (WindowsApplication1, …). It is helpful if you use a name that identifies you as well as the assignment (e.g. yourlastname assignment 6).

Background Knowledge:

• Each person with the flu passes it on to a certain number of people the next week depending on the severity level of the outbreak. With severity level 1, they pass it on to two other people, with severity level 2, the pass it on to three other people, … with severity level 10, they pass it on to 11 other people (see the pattern ?)
• 90% of the people with the flu in a given week recover by the next week. It doesn’t matter what medicine they take. There is no cure!!!
• Nobody dies!
• NOTE: It is very important that you calculate BOTH the number of new people infected AND the number of people recovering based on the same group of infected people. E.g. if 10 people are infected by a severity 1 outbreak, 9 will have recovered by the next week – but not before infecting 20 other people – resulting in 21 infected people the next week
• There is no need to worry about individuals; everybody is just a number!
• The number of infected people and the severity level are both always whole numbers.

Task Details:

• We’re no longer going to assume that the user enters valid and reasonable values, so ensure that the starting number of infected people, the severity level, and the number of weeks to simulate are numbers (and whole numbers for that matter), and have valid values  – let’s assume that the starting number of infected people has to be positive, the severity level needs to be 1-10, and the number of weeks is between 2 and 1000. Don’t try to calculate anything if bad data has been entered (display a message).   
• HINT: You can use a ComboBox in the GUI for the user to specify the severity of the outbreak. The Items property of a ComboBox allows you to specify the possible values to choose from. The user’s selection is available as comboboxname.SelectedItem.ToString() which can then be TryParse’d into an Integer. If that sounds like a hassle, note that it means that you can guarantee valid user input without any validation code!  You might alternatively use the SelectedIndex property which gives which number item was selected (be careful!)
• HINT: You (if you think about this) do NOT have to nest all branches inside each other (e.g. for validation) if you are careful!!! If you check one input thoroughly and set a boolean (e.g. weeksOk), that boolean can be checked later to see if it was previously found ok or not.
• When 90% of people recover, a straight calculation of 90% could result in a non-whole number of people (which is not possible). You must ROUND the result, however the round method produces a double. Instead, I recommend using the Convert.ToInt32 method – which has as a parameter the value to be converted to an integer and produces an integer – which is rounded!!
• To add items to the rich text box, as discussed in class, use richtextboxname.AppendText( a string ). You can build a string out of pieces using “concatenation” . E.g.  “Week: “ & week.toString() & …  …   & ControlChars.NewLine

(The ControlChars.NewLine moves the next info after to a new line). To clear the contents of a list box, use richtextboxname.Clear()

• Clear can set input values to defaults instead of clearing, if desired.

• MAKE SURE YOUR PROGRAM WORKS! (i.e. gets the correct answers) - it doesn’t have to just run, it needs to run correctly!  Now that our program is branching, we need to try more examples to make sure that they work. We want all paths through the program to work correctly. Think, “what different possibilities need to be checked?”For instance, does your program do the right thing no matter how many inputs are invalid?

Miscellaneous:

• You must turn on Option Strict and Option Explicit
• Put YOUR NAME, e-mail address, date, and purpose of the program in comments at the beginning of the program. The purpose should be what the program is supposed to do, not the learning goals.  
• You MUST include comments that explain your program in order to get full credit.
• Name all textboxes and buttons meaningfully, and use conventions for ending their names. Also, any labels referred to in code should also be named meaningfully.
• Any variables that you declare should have meaningful names – descriptive of the data that they hold.
• Make any textboxes that user should never enter a value in “Read Only” (or use labels instead!)
• Put your name on the form as a Label or as part of the form title.
• Try to use good user interface design. Make clear what user needs to do and what the answers mean.

Hand in:

• Compressed (zipped) folder with your entire project containing all files related to the project, submitted to Blackboard.  Please name the zip file something along the lines of yournameAssignment5
• Print out of your code.