2.3 Robust Programs

Question 1

What is Validation ?

Answer 1

Ensuring that any data input is possible and sensible.

Question 1

What is a range check ?

Answer 1

the input must fall within a specified range.

Question 2

What is a length check ?

Answer 2

the input must not be too long or too short.

Question 3

What is a presence check ?

Answer 3

a data value must be entered

Question 4

What is a format check ?

Answer 4

the data must be in the correct format

Question 5

What is a type check ?

Answer 5

the data must be of a specified data type

Question 6

What is a verification check ?

Answer 6

they repeat the entered data to the user and ask them to confirm if this data is correct.`

Question 7

What is authentication ?

Answer 7

the process of a user confirming that they are who they say they are on a computer system

Question 8

What are the 3 factors of authentication?

Answer 8

• something you are - username
• something you know - password
• something you have - swipe card, biometrics

Question 9

What is the purpose of defensive design ?

Answer 9

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

Question 10

What are the 3 areas of defensive design?

Answer 10

• protection against unexpected user inputs
• maintainability
• minimising/removing bugs

Question 11

How are anticipation and protection applied ?

Answer 11

• validation
• sanitisation

-authentication

-maintenance

• testing

Question 12

What is the purpose of maintainability ?

Answer 12

to ensure that, over time, a program can be easily maintained.

Question 13

How to increase maintainability ?

Answer 13

• Using comments
• Using naming conventions
• Using indentation

Question 14

What are comments ?

Answer 14

Lines in programs that provide information about what the different parts of the program do.

Question 15

What are naming conventions ?

Answer 15

Choosing a variable name that reflects the purpose of the variable.

Question 16

What is Indentation ?

Answer 16

Code within selections or iterations should be indented

Question 17

What are subprograms ?

Answer 17

small programs that are written within a larger, main program.

Question 18

What are the two types of subprograms ?

Answer 18

• procedures
• functions

Question 19

What are the benefits of subprograms ?

Answer 19

• small in size - easier to write, test and debug
• can be saved separately as modules - used again in other programs
• may be used repeatedly at various points in the main program.

Question 20

What is a procedure ?

Answer 20

A procedure is a subprogram that performs a specific task

Question 21

How is a procedure run ?

Answer 21

A procedure is run by calling it.

Question 22

What is a function ?

Answer 22

works in the same way as a procedure, except that it manipulates data and returns a result back to the main program.

Question 23

How is a function run ?

Answer 23

A function is run by calling it.

Question 24

What are Libraries ?

Answer 24

contain pre-written, tested functions that extend the functionality of a language.

Question 25

What are syntax errors ?

Answer 25

Not following syntax rules governing how to write statements

Question 26

What are logic errors ?

Answer 26

Does not cause a program to crash but causes unexpected results.

Question 27

What are the two types of testing ?

Answer 27

• Iterative
• Final (terminal)

Question 28

What is iterative testing ?

Answer 28

Carried out while a program is being developed - repeats (iterates) until the module works as intended.

Question 29

What is final (terminal) testing ?

Answer 29

All modules are complete and the program is tested as a whole

Question 30

What is valid testing data ?

Answer 30

• sensible, possible data that the program should accept and be able to process.

Question 31

What is extreme testing data ?

Answer 31

• valid data that falls at the boundary of any possible ranges

Question 32

What is invalid (erroneous) testing data ?

Answer 32

• data that the program cannot process and should not accept.

Question 33

What is a test plan ?

Answer 33

A list of what is to be tested and how it is to be tested.

Question 34

What are bugs ?

Answer 34

An error in a program.