producing robust programs

producing robust programs

1. defensive design

   • protection against user inputs
   • maintainability
     • comments
     • indentation
     • formatting
   • minimising/removing bugs
   • validation
     • makes sure data entered is sensible and reasonable
       • type check
       • length check
       • format check
       • range check
       • presence check
   • testing
     • checks program functions as designed
     • checks it meets needs of end user
     • iterative testing
     • final testing
     • types of data used in testing
       • valid data
       • invalid data
       • borderline
   • authentication
     • usernames and passwords