Producing Robust Programs

Question 1

What is the purpose of defensive design?

Answer 1

To ensure that a program runs correctly and continues to run no matter what actions a user takes

Question 2

State 4 methods of creating a defensive design

Answer 2

• Validation
• Authentication
• Maintenance
• Testing

Question 3

What is data sanitisation?

Answer 3

Hiding or protecting data so it cannot be seen or disclosed

Question 4

What is validation?

Answer 4

The process of ensuring an input is possible and sensible

Question 5

Give 5 examples of checks that can be done to validate an input

Answer 5

• Range check
• Presence check
• Length check
• Format check
• Type check

Question 6

What is a range check?

Answer 6

A check that ensures an input is within a specified range

Question 7

What is a presence check?

Answer 7

A check to see if anything was inputted

Question 8

What is a length check?

Answer 8

A check that ensures an input isn’t too long or short

Question 9

What is a format check?

Answer 9

A check to ensure the input is in the right format

Question 10

What is a type check?

Answer 10

A check to ensure the input is in the specified data type

Question 11

What is authentication?

Answer 11

The process of ensuring a person is who they say they are

Question 12

Name 3 ways of authenticating a user

Answer 12

• Usernames & passwords
• Biometrics
• PIN number

Question 13

Name 4 ways of making a program maintainable

Answer 13

Using:

• Comments
• Naming conventions
• Indentation
• Using subprograms

Question 14

What are the two types of subprogram?

Answer 14

• Functions
• Procedures

Question 15

What is the difference between a function and a procedure?

Answer 15

Functions return a value, procedures do not

Question 16

What is the purpose of testing?

Answer 16

To ensure the program runs as intended by removing all syntax and logic error

Question 17

What are the two types of testing?

Answer 17

• Iterative testing
• Final testing

Question 18

What is another name for final testing?

Answer 18

Terminal testing

Question 19

When is iterative testing done?

Answer 19

When a program is being developed

Question 20

When is final testing done?

Answer 20

When a program is complete

Question 21

How does iterative testing work?

Answer 21

• After a module of code is written it is tested
• The code will then be edited
• This process repeats until the module works as intended

Question 22

What is final testing?

Answer 22

When the entire program is tested to see if it works as intended

Question 23

What are the 4 different data types used in testing?

Answer 23

• Normal data
• Boundary data
• Invalid data
• Erroneous data

Question 24

What is normal test data?

Answer 24

Data which should be accepted by the program without causing errors

Question 25

What is boundary data?

Answer 25

Data of the correct type which is on the very edge of being valid

Question 26

What is invalid test data?

Answer 26

Data of the correct type which should be rejected by a computer system

Question 27

What is erroneous data?

Answer 27

Data of the incorrect type which should be rejected by a computer system

Question 28

How can you record testing?

Answer 28

With a test table

Question 29

What columns should be on a test table?

Answer 29

• Test number
• Description of what is being tested
• Test data being used
• Type of test data
• Expected result
• Actual result