Producing robust programs

Question 1

input validation techniques

Answer 1

• type check
• range check
• presence check
• format check
• length check

Question 1

Anticipating misuse

Answer 1

• division by zero
• communication error
• printer and other peripheral errors
• disk errors

Question 2

Authentication

Answer 2

A way to confirm a user identity usually by usernames and passwords

Question 3

How to increase the security of pass-based authentication systems?

Answer 3

• force user to use strong passwords
  and change it regularly
• limit the num of failed attempts

Question 4

Ways to maintain program

Answer 4

• comments
• white space
• indentation
• descriptive variable names
• functions
• constants at top of program

Question 5

Comments use

Answer 5

• explain program
• explain section of code
• visually divide sections of program

Question 6

White space use

Answer 6

• makes sections of program easier to see

Question 7

Indentation use

Answer 7

• for every selection and iteration
  branch

Question 8

reasons for testing

Answer 8

• ensure no errors in code
• check that program has an acceptable
  performance and usability
• ensure that unortharised access is
  prevented
• check if program meets the
  requirements

Question 9

What are the 2 types of testing

Answer 9

• iterative testing
• terminal testing

Question 10

Iterative testing

Answer 10

• each new module is tested as it is
  written
• program branches checked for
  functionality
• checking new modules dont introduce
  new errors in existing code
• ensures the program handles
  erroneous data and exceptional
  situations

Question 11

terminal testing

Answer 11

• all modules work together
• program produces required results
  with normal, boundary, invalid and
  erroneous data
• program meets the requirements with
  real data
• beta test may find more errors

Question 12

types of data tests

Answer 12

• normal inputs
• boundary input
• invalid input
• erroneous input

Question 13

How to make an algorithm more robust

Answer 13

• writing code which anticipates a range
  of possible inputs
• those input could be invalid or
  erroneous data
• making sure bad data doesnt crash
  the program
• making sure prompts to the user are
  descriptive and helpful
• making sure only data of the correct
  “data type” are entered
• checking and handling missing or
  black data