2.3 Robust Programming

Question 1

Defensive Design Considerations

Answer 1

• Authentication
• Anticipating misuse

Question 2

Authentication

Answer 2

Verifying the identity of a user.

Question 3

Examples of Authentication

Answer 3

Username, password or biometrics

Question 4

Anticipating Misuse

Answer 4

Designing a program in a way that is resilient to potential misuse.

Question 5

Types of Anticipating Misuse

Answer 5

• Division by 0
• Communication error

Question 6

Validation

Answer 6

Checking input data is sensible and in the right format.

Question 7

Types of Input Validation

Answer 7

-Type check
- Range check
- Presence check
- Format check
- Length check

Question 8

Type Check

Answer 8

Is the input the correct data type?
E.g. Inputting an integer where it asks for a name.

Question 9

Range Check

Answer 9

Is the input within range?
E.g. Inputting 1000 where it asks for age

Question 10

Presence Check

Answer 10

Has required data been entered?
E.g. Mandatory questions on google form

Question 11

Format Check

Answer 11

Correct format?
E.g. DD/MM/YYYY

Question 12

Length Check

Answer 12

Does the input have the correct number of characters?
E.g. 8 character password

Question 13

Advantages of Input Validation

Answer 13

• Make a program more robust
• More user friendly
• Prevents further errors later on

Question 14

Maintainability

Answer 14

The process of ensuring that a program is easy to understand, modify and update.

Question 15

Maintainability Techniques

Answer 15

• Use of subprograms
• White space
• Indentation
• Relevant variable names
• Comments

Question 16

Use of subprograms

Answer 16

They give the code structure and make the purpose of the code clear.

Question 17

White space

Answer 17

Separates sections of code to make them visually clearer.

Question 18

Indentation

Answer 18

Makes it clear which lines of code are part of iteration statements.

Question 19

Relevant variable names

Answer 19

Appropriate variable names mean that understanding the purpose of the variable will be easier.

Question 20

Comments

Answer 20

Provide information about what the different parts of the program do.

Question 21

Purpose of Testing

Answer 21

To remove bugs and to ensure that the program functions as intended.

Question 22

Types of Testing

Answer 22

• Iterative testing
• Terminal testing

Question 23

Iterative Testing

Answer 23

Carried out while a program is being developed. The programmer writes a section of code (module) then tests it.

Question 24

Terminal / Final Testing

Answer 24

Carried out after all the modules are complete to ensure the code functions as it should.

Question 25

Syntax Error

Answer 25

Errors which break the grammatical rules of the programming language and stop it from being run.

Question 26

Logic Error

Answer 26

Errors which produce unexpected output.

Question 27

Normal Test Data

Answer 27

Sensible, possible data that a program should accept and be able to process.

Question 28

Boundary Test Data

Answer 28

Valid data that falls at the boundary of any possible ranges.

Question 29

Erroneous Test Data

Answer 29

Data that a program cannot process and should not accept.