2.3 New

Question 1

Defensive design

Answer 1

Approach to software development where every possible input from a user is considered

Question 2

Purpose of defensive design

Answer 2

-to anticipate ways a user could misuse a program
-ensure the final program is robust and reliable for all users

Question 3

What can developers do to anticipate errors in programs

Answer 3

Ensure the software has a way of dealing with the potential errors to ensure software does not crash

Question 4

Examples of error in programs

Answer 4

-peripheral errors
-disk errors
-communication errors

Question 5

Peripheral error

Answer 5

-When peripherals do not perform as intended
-eg printer runs out of paper(fix is allow user to reprinting document after refilling the paper)

Question 6

Disk error

Answer 6

-Error that occur on a disk
-such as disk running out of space(fix=allowing user to save work on another disk)

Question 7

Communication errors

Answer 7

Applications using online systems losing online connection to the host server(fix = automatically retry if connection resumes)

Question 8

Authentication

Answer 8

Process of ensuring that a system is secure by asking the user to complete tasks to prove they are an authorised user of the system

Question 9

Examples of authentication

Answer 9

-Usernames and passwords
-CAPTCHA

Question 10

Input validation

Answer 10

Code which is used to check that an input from a user is acceptable and matches the requirements of the program

Question 11

What are the 5 main categories of validation

Answer 11

Length check
Type check
Range check
Presence check
Format check

Question 12

Type check

Answer 12

Checking if what is entered is a certain data type such as integers for age

Question 13

Range check

Answer 13

Ensuring data entered falls under a particular range such as between 0-100 for age

Question 14

Length check

Answer 14

Checks the length of a string and checks if it meets the condition

Question 15

Presence check

Answer 15

Looks to check if any data has been entered in a field

Question 16

Format check

Answer 16

Ensures that the data has been entered in the correct formate such as email containing @ and . symbol

Question 17

Program maintainability

Answer 17

Ensuring programmers can easily understand what a program is doing a long time after having written it

Question 18

How are programs maintained

Answer 18

-commenting of code
-white space(makes each section clear)
-indentation
-sensible variable names
-use of sub programs

Question 19

Purpose of testing programs

Answer 19

-ensure there are no errors or bugs in the code
-ensure that the code performs as it was intended
-ensure no one can gain unauthorised access to the system
-check the program solves in the initial problem and meets all requirements

Question 20

Types of testing programs

Answer 20

Iterative testing
Final testing

Question 21

Iterative testing

Answer 21

-each part of program is tested
-every pathway through the program is tested(if statements)
-done during development of program
-make changes and improvements while testing

Question 22

Final testing

Answer 22

-Testing that all parts of a program work together
-checking the program against real data to ensure it meets all of the requirements
-testing program using normal, boundary and erroneous data
-done towards end of development
-can alpha testing or beta testing

Question 23

How to identify syntax errors

Answer 23

-program will not execute when there is a syntax error (IDE provides information about the error)

Question 24

How to identify logic errors

Answer 24

-Program runs but expected output is not produced
-check obvious areas such as logical and Boolean operators or division by 0

Question 25

Categories of tests

Answer 25

Normal tests
Boundary tests
Erroneous tests
Invalid tests

Question 26

Normal test

Answer 26

When a user enters data that should be accepted in the program

Question 27

Boundary tests

Answer 27

When a user enters data that is on the edge of what is acceptable

Question 28

Erroneous tests

Answer 28

When a user enters data that is the wrong data type

Question 29

Invalid tests

Answer 29

When a user enters data that is the right data type but outside of what is accepted