2.3.1

Question 1

what is defensive design?

Answer 1

the practice of anticipating every possible way that a user could misuse a system or device

Question 2

a defensive design has not been good enough when:

Answer 2

-the program crashes
-the program behaves in an unintended fashion
-data security has been compromised

Question 3

what does defensive design anticipate?

Answer 3

it anticipates misuse and uses authentication

Question 4

what’s the first part of defensive design?

Answer 4

to decide what type of user interface to use: command line interface, graphical interface, menu driven interface

Question 5

what’s the second part of defensive design?

Answer 5

considering how data is entered- using widgets is a way of limiting data entries and preventing entry errors

Question 6

what’s the third part of defensive design?

Answer 6

when data is entered into a program it is important that it is valid in order for the program to operate correctly

Question 7

validation

Answer 7

check made by a computer to ensure that the data entered is sensible or reasonable

Question 8

what are the different types of validation checks?

Answer 8

-presence check
-range check
-type check
-format check
-lookup check
-contingencies

Question 9

presence check

Answer 9

makes sure the data has been entered in a particular field

Question 10

range check

Answer 10

ensures the data is within a certain limit

Question 11

type check

Answer 11

ensures the data is in the correct data type

Question 12

format check

Answer 12

ensures the data entered matches a particular pattern

Question 13

lookup check

Answer 13

checks to see if the data exists in a list

Question 14

contingencies

Answer 14

unexpected events, this could include: invalid input of data, file missing ect.

Question 15

global

Answer 15

the variable can be used outside a function

Question 16

what can be used to increase the maintainability of a program?

Answer 16

-sub programs
-naming conventions
-indentation
-commenting

Question 17

why is maintenance of a business needed?

Answer 17

-errors are found in the software
-a security loophole could be found
-customer would like improvements
-external factors could change

Question 18

what needs to happen to carry out maintenance on a code?

Answer 18

-the programmer needs to understand the code

Question 19

identifier

Answer 19

a word chosen by the programmer to identify the constant or subroutine (must be unique and have no spaces)

Question 20

comments

Answer 20

explain what each part of the code does and makes it easier to understand what they wrote and why

Question 21

constant

Answer 21

if a value does not need to change when a program is running it can be a constant

Question 22

indentation

Answer 22

helps to show a programmer where a block of code finishes, important for understanding how a code works

Question 23

white space

Answer 23

leaving a line gap between sections of code makes it more readable

Question 24

subprograms

Answer 24

makes programs more readable as the detail of each subroutine can be ignored when looking at the whole program