producing robust programs

producing robust programs

1. defensive design

   • protective against unexpected user input
     • validation- the process of insuring data entered is sensible or reasonable
       • type check
       • length check
       • format check
       • range check
       • presence check/ null check
   • maintainability
     • maintainability is a defence strategy that is used to insure that code is maintainable. this means that you code is writen in such a way that other devs can read the code. this reduces the chance for bugs / mistakes
       • comments
       • indentation
       • formatting(subroutenes)
   • minimising/ removing bugs
     • testing is required to insure that a developed program functions as it was designed and meats the needs of the end user
       • iterative testing- testing while the code is being developed
       • final testing- testing at the end of the development
       • test plans are plans used to ensure a system is fully tested. you use different type of data to do this
         • valid data- should produce the expected result
         • invalid data - should produce a error
         • borderline- used to test the edge between valid and invalid are dealt with correctly

2. authentication

   • this checks that the right people are logging on
     • usernames and passwords
     • have complex passwords and update them regularly
     • limit login attempts