System controls

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Which is an example of a system control?

A A form that accepts any value typed in

B A form that rejects an age of -5

2. What is the main purpose of a system control?

A Keep the system's behaviour within what is intended

B Make the system's screen look more colourful

3. A login screen only lets a student see their own marks. Which type of control is this?

A Access limit

B Feedback

4. A page shows 'Order saved!' after you press Submit. Which type of control is this?

A Feedback

B Input control

5. Which is an input control?

A A progress bar that shows a file uploading

B A range check that only accepts marks from 0 to 100

Match the Pairs

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

Left column		Right column
1if not age.isdigit():		ANo input control: a non-number or a negative quantity is passed straight to the order, which can crash the system
2if role != "admin":		BNo access limit: the program welcomes the user without checking the password, so anyone gets in
3Feedback control: the system tells the user what happened so they can correct their action		CAn input control: it checks the data type and rejects non-numeric input before the system uses it
4Input control: reject values outside the allowed range		Dprint("Error: enter a number from 1 to 10")
5password = input() print("Welcome")		EAn access limit: it stops users who are not administrators from reaching restricted actions
6qty = int(input()) order(qty)		Fif mark < 0 or mark > 100:

Definitions

system control

Fill in the Blanks

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

if age >= 0 ___ age <= 120: print("Valid age")

value = input("Enter a number: ") while ___ value.isdigit(): value = input("Try again: ")

if score < 0: _____("Score cannot be negative")

if role __ "admin": print("Access denied")

attempts = 0 while attempts < 3: attempts __ 1

Spot the Error

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

Question 1

A age = int(input("Age: "))

B while age < 0 or age > 120:

C age = input("Again: ")

D print("Age saved")

Question 2

A role = "student"

B if role == "admin":

C print("Access denied")

D else:

E print("Access denied")

Question 3

A pw = input("Password: ")

B if len(pw) = 8:

C print("Password saved")

D else:

E print("Too short")

Question 4

A attempts = 3

B while attempts < 3:

C pin = input("PIN: ")

D attempts += 1

Question 5

A def check_qty(qty)

B if qty < 1 or qty > 10:

C return False

D return True

Answer Key

System controls

Section A: Quick Questions

B — A form that rejects an age of -5

A — Keep the system's behaviour within what is intended

A — Access limit

A — Feedback

B — A range check that only accepts marks from 0 to 100

Section B: Match the Pairs

if not age.isdigit(): → An input control: it checks the data type and rejects non-numeric input before the system uses it

if role != "admin": → An access limit: it stops users who are not administrators from reaching restricted actions

Feedback control: the system tells the user what happened so they can correct their action → print("Error: enter a number from 1 to 10")

Input control: reject values outside the allowed range → if mark < 0 or mark > 100:

password = input() print("Welcome") → No access limit: the program welcomes the user without checking the password, so anyone gets in

qty = int(input()) order(qty) → No input control: a non-number or a negative quantity is passed straight to the order, which can crash the system

Section C: Definitions

system control — A mechanism, such as input validation, user feedback or access limits, that keeps a system's behaviour within what is intended.

Section D: Fill in the Blanks

if age >= 0 and age <= 120:
    print("Valid age")

value = input("Enter a number: ")
while not value.isdigit():
    value = input("Try again: ")

if score < 0:
    print("Score cannot be negative")

if role != "admin":
    print("Access denied")

attempts = 0
while attempts < 3:
    attempts += 1

Section E: Spot the Error

C — The re-entered value is left as a string, so the range check on the next loop would crash or fail. It should be converted with int(input("Again: ")) so the input control keeps working.

C — This access limit gives the wrong feedback. An admin should see "Access granted", and "Access denied" belongs in the else branch.

B — A single = assigns a value and is a syntax error in a condition. The length check needs a comparison operator: if len(pw) >= 8:

A — The attempts counter must start at 0. Starting at 3 means the loop never runs and the user is never asked for a PIN, so the access limit does nothing.

A — The def line is missing its colon. It should be def check_qty(qty): so this input control function is valid Python.