Modular Design

1
Modular Design

• Top-Down Design

2
Top-Down Design

• Design is represented by a hierarchy chart.
• Break a problem into individual tasks or modules.
• If a module is too complex, break it down into
  sub modules.
• Transcribe the modules into pseudocode.
• Code the modules using the three logical
  structures of sequences, decisions, and
  repetition.

3
Top-Down Design Criteria

• The design should be easily readable and
  emphasize small module size.
• Modules proceed from general to specific as you
  read down the chart.
• The modules, as much as possible, should only
  perform a single well-defined task.
• Modules should be as independent of each other as
  possible.

4

• Write a financial program that displays the
  monthly payment and total payment on a loan given
  the loan amount, yearly interest rate and loan
  duration (in years). The formula used to
  calculate the monthly payment is (SM (M1)
  N)/( (M1)N)-1)
• Where
• M monthly interest rateN number of monthly
  paymentsS loan amount

5
Loan Program
Get Input
Make Calculations
Display Results
6
Loan Program
Get Input
Make Calculations
Display Results
Get Amount
Get Duration
Get Interest Rate
Display Headings
Display Amounts
Compute Monthly Payment
Compute Total Payment
7
Loan Program
Get Input
Make Calculations
Display Results
Get Amount
Get Duration
Get Interest Rate
Display Headings
Display Amounts
Compute Monthly Payment
Compute Total Payment
Compute Monthly Interest Rate
Compute Number of Months