Producing Robust Programs

Producing Robust Programs

1. defensive design

   • a strategy to make program more robust
     • protection against unexpected inputs
       • validataion
         • process of ensuring data is sensible
         • type check (correct data types)
         • length check
         • format check(check its a certain pattern)
         • range check(numbers fall within limits)
         • presence check(nothing has been left blank)
     • maintainability
       • commenting(understand what the code does)
       • indentation
       • formatting(subroutines)
       • name conventions
     • removing bugs
       • testing
         • iterative
           • testing whilst developing your program
         • final
           • once program is finished program is tested against requirements
         • they use a test table
   • valid data
   • invalid data
   • borderline
   • authentication
     • usernames and passwords
     • secure strong passwords