Producing Robust Programs

Producing Robust Programs

1. Robust

   • Won't break/function correctly
   • must be secure if not data could be comprimised

2. Defensive design

   • Protection against unexpected user input
     • Validation
       • Make sure input is sensible and resonable
         • Check data type
         • Check length
         • Check format
         • Check range
         • Check presence
   • Maintainability- ensure code is readable and understandable
     • Reduced chance of bugs
     • Comments- for explanation
     • Indentation-improves indentation
     • Formatting-creates sub-routine makes it shorter
     • Constants- stops repetition of values which will stay the same
   • Minimising bugs
     • Iterative Testing
       • Testing throughout development
       • Final Testing tested at end of development, against the requirements of the customer
       • Valid data will produce expected results
       • Invalid data should produce an error, won't crash
       • Borderline data on the edge between valid and invalid dealt with correctly by the program
   • Ensures that program will run correctly and continue no matter what
   • Authentication
     • Login with correct login credential
     • Access rights
       • Different rights depending on levels
     • Limit login attempts