Creating Robust Programs

Question 1

What is anticipation and protection done through?

Answer 1

Validation 
Sanitation
Authentication
Maintenance
Testing

Question 2

What is a defensive design?

Answer 2

A program that runs correctly and continues to run no matter the user input.

Question 3

How may programers apply defensive design?

Answer 3

Anticipating how users may misuse their program then attempt to prevent it
Ensure their code is well maintained
Minimising the number of errors through testing

Question 4

What is the best way to prevent a user from accidentally or intentionally misusing a program when entering data?

Answer 4

Through input validation

Question 5

What is validation?

Answer 5

Checking if data meets certain criteria before passing into the program

Question 6

Name the different types of validation.

Answer 6

Range check
Presence check
Format check
Look up table
Length check

Question 7

Describe what a range check does?

Answer 7

Checks the data is within a specified range

Question 8

Describe what a presence check does?

Answer 8

Checks the data has actually been entered

Question 9

Describe what look up table does

Answer 9

Checks the data against a table of acceptable values

Question 10

Describe what a length check does

Answer 10

Checks the data is the correct length

Question 11

Karen wants to validate usernames for an online forum. She wants each username to be longer than five characters and start with an upper case letter.
Give two validation checks Karen would need to use.

Answer 11

Length check - to make sure the username is not longer or shorter than the length allowed
Format check - To make sure the username starts with an uppercase letter

Question 12

Name a reason for authentication

Answer 12

Authentication helps protect your programs
It can confirm the identity of a user before they’re are allowed to access certain pieces of data or features of a program

Question 13

What are common ways to increase the security of a password based authentication system?

Answer 13

Force users to use strong passwords and have them change passwords regularly
Limit the number of failed authentication attempts before access to an account is lost
Ask for a random selection of characters from the password on each authentication

Question 14

Why is it important to get the level of authentication correct?

Answer 14

Too much authentication can affect a programs functionality and put people off using it

Question 15

Name two different types of errors

Answer 15

Syntax errors

Logic errors

Question 16

What is a syntax error?

Answer 16

An error in the code where the rules or grammar of the programming language have been broken

Question 17

What is a logic error?

Answer 17

When a program does something that was not intended