2.3 Robust Programs

• what is validation in programming?

  Validation is checking whether input data should be allowed or is sensible and follows criteria
• Types of validation

  1. Range Check - Checks data is sensible limits
  2. Type check - checks data is the correct data type
  3. Format check - checks data is entered in correct format
  4. Presence check - checks data is entered and not blank
  5. Length check - checks length of input is within certain amount
• What is authentication?

  Ensuring only allowed/ authorised user can gain access

  E.g username and password, number of bank account
• What is anticipating misuse?

  The practice of anticipating all possible way a user could misuse a device
• maintainability of a program

  1. comments- enables a programmer to understand the purpose of a line of code used
  2. indentation - improve readability and clearly shows each block of code
  3. naming conventions- using sensible names/ variables so it’s easier to understand
  4. use of sub-program - easier to debug code, reuse code and easier to test
• Purpose of testing:

  • to find errors and fix them
  • To ensure output is correct
  • End result meets user requirements
• Two types of testing are?

  • iterative testing
  • Final/terminal testing
• What is iterative testing?

  • tested during development
  • Programmer develops module tests it and repeats until module works as expected
• What is final/terminal testing?

  • tested after development and before program is released
  • Takes place once all module are tested so programs works as expected
• Test data

  • used to test wether a program is functioning properly
• Types of test data:

  1. valid data- sensible data that program should accept and be able to process
  2. boundary data - data at the extreme boundary of any data ranges , ensures that system only allows data up to the max and min value
  3. erroneous data- data that program can’t process and accept
• Two types of errors:

  • Syntax error
  • Logic error
• What is syntax error?

  • an error in the grammar of the program or an error that breaks the rules of the programming language
  • contain an error and will not run
• What is a logic error?

  • an error that results in incorrect output or unexpected result
  • contain error but still run and produce wrong output