CIS 234: Project 2 Issues

1
CIS 234 Project 2 Issues

• Dr. Ralph D. Westfall
• May, 2010

2
Avoid Copy and Paste Reuse

• don't copy and paste code to do something very
  similar with different data
• put repeated code in a method, then call that
  method with different data
• method may be in same class, or in a different
  class (e.g., FICA/Medicare calculations work like
  FIT calculations)

3
Repeat This With Me

• "If I'm copying and pasting code, and then
  changing it slightly, I'm probably doing
  something wrong."
• all together
• left side of the room say the green text, then
  middle say blue text, and finally right side say
  red text (then 3-part harmony?)
• the more lines x often, the more wrong

4
Avoid Duplicated Activities

• data
• don't get same data again and again
• store value in a variable the first time, then
  use that instead of going back to source
• calculations
• don't repeat them
• store value in a variable the first time, and
  then recycle that as needed

5
Separate Data Calculations

• put ALL data in a separate class e.g., Inputs.
  java
• possibly with the exception of trivial items such
  as MONTHS_IN_YEAR
• don't do any calculations in the class that holds
  the data

6
Inheritance

• when a class inherits from another class, you can
  (and should) use the new class to do what the
  previous one did
• a class named NuEmployee that inherits from
  Employee should now do the income tax (FIT)
  calculations that Employee did
• do NOT create objects from both, and use Employee
  class objects to calculate FIT

7
Excel File

• intended to check calculations in Java
• if just plug output data into it, without any
  formulas, nothing gets checked
• all subtotals and totals should be calculated in
  Excel
• formulas should also multiply items per day times
  days per year time prices, and times costs

8
Code

• appropriately formatted with skipped lines
• put all declarations before any of the action
  code in a method
• no redundant items e.g.,
• use comments where necessary, delete ones that
  are unnecessary or are no longer appropriate

9
Follow the Requirements

• Excel file missing in a lot of projects
• pseudocode too
• a few zip or Word files weren't named with last
  and first name
• output needs to be pasted in Word file
• code needs to be pasted into Word file
• JOptionPane should be in Inputs class

10
Requirements Really Do Count

• several students didn't make the output show the
  kangas and hanboks per day, or missed other
  requirements for output
• some didn't use a separate class to calculate
  Other Operating Expense
• a few didn't notice that some data items had been
  updated (red font)

11
Use Feedback

• Project 1 grading identified problems with
  Mortgage calculations
• a few students still didn't convert monthly
  payment to annual occupancy expense
• at least one student still used the percentage
  value (6.5) instead of the decimal value (0.065)
  in the calculation

12
Variable Names

• should make it clear what the data is
• total and subtotal aren't good, because they
  could apply to a lot of different things
• instead use names such as incomeTotal,
  productCostSubtotal, kangasPerYear,
  employeeExpenseSubtotal,
• use naming convention lower case for first word,
  Upper Case to start each added one