Producing a Robust Programs

Producing a Robust Programs

1. Maintainability

2. Sanitisation

3. validation

   • A programmer should consider that any inputs a user makes may be incorrect and should plan arrangements for such unexpected actions. Using validation helps a programmer to ensure that any data input is possible and sensible.
   • Validation applies rules to inputted data. If the data does not follow the rules, it is rejected, reducing the risk that incorrectly input data may crash a program.
   • A programmer can build various types of validation into a program:
     • Length check - the input must not be too long or too short. For example, a surname will require at least one letter, but is unlikely to require more than 40.
       • Format check - the data must be in the correct format, such as entering a date in the format DD/MM/YYYY.
         • Type check - the data must be of a specified data type, such as an integer when specifying a quantity.
           • presence check - a username must be entered
             • range check - age restrictions may require the user's date of birth to be before a certain date
               • long type check - the password may need to have a mixture of upper and lower case letters, a number and a special character
                 • length check - a password must be at least eight characters
                   • format check - the user's date of birth must be entered in the specified format

4. Authentication

   • authentication Verifying the identity of a user