The user interface as part of a system model

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Quick Questions

Shade in the A or B circle for each question.

1. On a conceptual model, where is the user interface placed?

A Outside the model, because it is not part of the system

B On the system boundary, linking the user and the system

2. Which describes the role of the user interface in a system?

A Where the user gives inputs and receives outputs

B Where the database stores data permanently

3. A student types their username and password into a login screen. What is this?

A A user input passing through the interface

B A system output passing through the interface

4. A mobile app shows an order confirmation message on screen. What is this?

A A system output shown to the user

B A user input given to the system

5. Which is an example of the user interface in a conceptual model for a school canteen app?

A The server hardware that runs the app in the background

B The ordering screen where students pick items and see their total

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1user interface		AThe part of the system where the user gives inputs and receives outputs
2User → Interface → Processing		BA user input travelling through the interface into the system
3The interface sits on the system boundary as the link between the user and the system		CSystem processing → Interface → User (report on screen)
4Outputs from the system are shown to the user through the interface		DA prompt displayed to the user is a system output, not a user input. Inputs go from the user into the interface, such as typing a username.
5[User] → [Database] (no interface drawn)		E[User] <-> \|Interface\| <-> [System processing]
6Interface → User: "Enter username" (labelled as an input)		FThe user is linked straight to the database. The interface should be drawn on the boundary between them, as the link the user inputs and outputs pass through.

Definitions

user interface

Fill in the Blanks

Complete each line of code by filling in the missing parts.

Input: User -> _________ -> System

name = _____("Enter your name: ")

_____("Total: " + str(total))

# The interface sits on the system ________

Output: System -> Interface -> ____

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A def show_menu()

B print('1. Check balance')

C choice = input('Choose: ')

D return choice

Question 2

A def login_screen():

B user = print('Username: ')

C print('Welcome,', user)

D return user

Question 3

A def ui_output(score):

B msg = 'Your score: '

C print(msg + score)

Question 4

A ui_inputs = ['username', 'pin']

B ui_outputs = ['pin', 'balance']

C print(ui_inputs, ui_outputs)

Question 5

A def atm_ui():

B pin = input('PIN: ')

C amount = input('Amount: ')

D if pin = '1234':

E print('Cash:', amount)

Answer Key

The user interface as part of a system model

Section A: Quick Questions

B — On the system boundary, linking the user and the system

A — Where the user gives inputs and receives outputs

A — A user input passing through the interface

A — A system output shown to the user

B — The ordering screen where students pick items and see their total

Section B: Match the Pairs

user interface → The part of the system where the user gives inputs and receives outputs

User → Interface → Processing → A user input travelling through the interface into the system

The interface sits on the system boundary as the link between the user and the system → [User] <-> |Interface| <-> [System processing]

Outputs from the system are shown to the user through the interface → System processing → Interface → User (report on screen)

[User] → [Database] (no interface drawn) → The user is linked straight to the database. The interface should be drawn on the boundary between them, as the link the user inputs and outputs pass through.

Interface → User: "Enter username" (labelled as an input) → A prompt displayed to the user is a system output, not a user input. Inputs go from the user into the interface, such as typing a username.

Section C: Definitions

user interface — The part of a system where the user gives inputs and receives outputs. On a conceptual model it sits on the system boundary as the link between the user and the system.

Section D: Fill in the Blanks

Input: User -> Interface -> System

name = input("Enter your name: ")

print("Total: " + str(total))

# The interface sits on the system boundary

Output: System -> Interface -> User

Section E: Spot the Error

A — A function header must end with a colon. It should be def show_menu():

B — The interface takes the user's input with input(), not print(). print() only shows output. It should be user = input('Username: ').

C — A string cannot be joined to a number. The score must be converted first, so it should be print(msg + str(score)).

B — A PIN is typed in by the user, so it is an input. It is not an output shown to the user. The outputs list should hold items such as 'balance' and 'error'.

D — A single = assigns a value. A condition needs == to compare. It should be if pin == '1234':