Input And Output (Ch6) (M2)

Question 1

If you input something incorrectly, what will happen to the output?

Answer 1

If you input something wrong, it will be processed and be outputted as something wrong.
This is known as Garbage In, Garbage Out (GIGO)
Simply, if you input wrong information, you will get wrong information back.

Question 2

What is validation? What doesn’t it check?

Answer 2

Validation is an automatic computer check to ensure that the data entered is sensible and reasonable. It doesn’t check the accuracy of data.

Question 3

Give three types of validation checks

Answer 3

Types of validation checks:

Prescence check, Range check, Length check, Format check, Spell check

Question 4

What does a range check check for?

Answer 4

A range check checks that the input falls within a specified range.
This is usually applied to numbers and dates, but can apply to characters.
For example, when making a payment to someone, the amount to be entered might be set to be greater than zero and not greater than the funds available.

Question 5

What does a length check check for?

Answer 5

Checks that the input is not too long or short.
For example, a surname will require at least one letter, but is unlikely to require more than 40.

Question 6

What does a prescence check check for?

Answer 6

A prescence check checks that a data value has been entered. For example, entering a quantity when placing an order.

Question 7

What does a format check check for?

Answer 7

A format check checks that the data is in the correct format, such as entering a date in the format DD/MM/YYYY.

Question 8

What does a type check check for?

Answer 8

A type check checks that the data must be of a specified data type, such as an integer when specifying a quantity.

Question 9

What is the purpose of data sanitisation?

Answer 9

The purpose of data sanitisation is to hide or protect data so it can’t be seen or disclosed.

Question 10

Give two examples of data sanitisation

Answer 10

Two examples of data sanitisation: masking and input sanitisation.

Question 11

What does masking do?

Answer 11

Masking hides visible data by replacing it with something else

Question 12

What does input sanitisation do?

Answer 12

Input sanitisation checks that data is entered and removes anything that might be potentially dangerous

Question 13

What is 2 factor authentication?

Answer 13

Two factor authentication is where the user enters in their username and password. An authentication code is then sent to the user’s mobile device. The user then has to enter their authentication code to log into the application.

Question 14

Give an example of a service/company that uses 2 factor authentication

Answer 14

Google drive, amazon, apple all use 2 factor authentication

Question 15

What is a lookup table?

Answer 15

A lookup table is a table of acceptable entries

Question 16

What is authentication?

Answer 16

Authentication is a technique used to prove online identity
It is a process where a user is confirming that they are who they say they are on a computer system.

Question 17

A user provides a login and password which is stored in a system. What is the problem with this?

Answer 17

This does not prove the actual person is entering this data, as might be the case with identity theft.

Question 18

What does single factor authentication include?

Answer 18

Single factor authentication includes inputting:
Username and password

Question 19

What does two factor authentication include?

Answer 19

Two factor authentication includes inputting:
Username and password
Password pin/phone call/text message

Question 20

Why is two factor authentication useful?

Answer 20

Two factor authentication makes it harder for hackers to gain access to your account

Question 21

Give a common example of authentication

Answer 21

Passwords are a common example of authentication

Question 22

Give one way you can increase the security of a password-based authentication system

Answer 22

Here are some common ways to increase the security of a password-based authentication system:

Force users to use strong passwords and have them change passwords regularly.
Limit the number of failed authentication attempts before access to an account is lost.
Ask for a random selection of characters from the password on each authentication.

Question 23

Why can too much authentication be a problem?

Answer 23

Too much authentication can affect a program’s functionality and put people off using it

Question 24

Give 4 features of a robust program

Answer 24

Features of a Robust Program:

Anticipating misuse, input sanitisation, validation, verification, authentication, maintainable code

Question 25

What is anticipating misuse?

Answer 25

Anticipating misuse is planning ahead to take steps against potential misuse

Question 26

Give two types of authentication

Answer 26

Types of Authentication:

SMS/Email Codes
Voice
Passwords
Fingerprint
Face Verification

Question 27

What is reCAPTCHA? What does it do?

Answer 27

It helps to protect websites from spam and abuse.
It is a type of CAPTCHA which is a test to tell humans and bots apart.

Question 28

What is a robust program?

Answer 28

A robust program is a program that can handle errors and other unexpected conditions in some reasonable way

Question 29

What does a well-maintained program allow for?

Answer 29

A well-maintained program makes it easy for other programmers to understand what the code does.
They should also be able to change parts of the source code without the risks of causing problems elsewhere in the code.

Question 30

Give two ways you can make a program maintainable

Answer 30

Examples of making a program maintainable include:

Using subprograms to reuse code and make them easier to test. This is called modularisation
Using indentation to improve readability and clearly show each ‘block’ of code
Appropriate variable names, using a naming convention, ensure the purpose of a variable is immediately understood
Comments enable a programmer to understand the purpose of each line of code. Crucial when working in a team.
Using constants is another method of improving maintainability. This keeps the program consistent, which makes it easier to read and debug a program.

Question 31

What is modularisation?

Answer 31

Modularisation is using subprograms to reuse code and make them easier to test

Question 32

Give a method used to make a program maintainable

Answer 32

Methods to make programs maintainable:
Sensible variable names, comments, indentation, appropriate variable names, using constants, using subprograms

Question 33

What do structure diagrams show?

Answer 33

Structure (or modular) diagrams show the smaller tasks of a larger program.

Question 34

Describe a structure diagram and how it is split up

Answer 34

Structure diagrams are made by decomposing the program that you want to write into manageable modules.
Each of those modules is then decomposed even further into smaller modules and eventually into modules that perform individual tasks.

Question 35

Give three advantages of using structure diagrams

Answer 35

Advantages of using structure diagrams:

Coding is easier because you’re only writing code to carry out very simple tasks.
Lots of programmers can work on one program as each module can be written independently.
It’s easier to test your program as each module can be tested individually.
Individual sub programs and modules can be fixed and updated without affecting the rest of the program.
You will be able to reuse the sub programs and modules in programs you write in the future.

Question 36

Data can be read from a file, using what mode?

Answer 36

Data can be read from a file using read mode

Question 37

What does using read mode do?

Answer 37

Using read mode protects the data from being accidently changed, preventing data from being written to a file

Question 38

In the read and write modes, a file is accessed using what?

Answer 38

The file is accessed using a file handle in both the Read and Write modes

Question 39

What is read mode?

Answer 39

Read mode is where you can access the file however you cannot make any changes

Question 40

What is write mode used for?

Answer 40

Write mode is used to write text to a file (Used to change the data contents of a file)

Question 41

What is write mode?

Answer 41

Write mode is where you can access the file and also make changes

Question 42

What is file handling?

Answer 42

File handling is the process of storing and manipulating data in a file using a program

Question 43

What are the three steps to writing data to a file?

Answer 43

Steps:
Open the file using the file path
Write data to the file
Close the file

Question 44

What can happen to an unclosed file?

Answer 44

An unclosed file may become corrupted or data may be lost

Question 45

Write an algorithm in pseudocode to read in the message ‘This is the text stored in a file!’ from a text file called ‘message.txt’

Answer 45

FileName = OpenRead(“message.txt”)
FileName.ReadLine()
FileName.Close()