Chapter 4 — Functions (🦸 Your Own Commands)

🎯 Mission

Imagine you're playing a game.

Every time the player wins, you want to show:

🎉 You Win!
+100 XP
+50 Coins

Would you write those 3 lines 50 times throughout your program?

❌ No.

Instead, create your own command:

showReward()

That's exactly what a function is.

A function is your own custom command.

🟢 LEVEL 1 — Survival

Q1

What is the main purpose of a function?

A) Store data

B) Repeat code without copying it everywhere

C) Compare values

D) Create tables

✅ Answer: B

💡 Write once, use many times.

Q2

Which keyword creates a function?

A) func

B) method

C) function

D) create

✅ Answer: C

Q3

function hello()
    print("Hello")
end

What did we just do?

A) Called the function

B) Created the function

C) Deleted the function

D) Printed Hello

✅ Answer: B

💡 The function exists now, but hasn't run yet.

Q4

function hello()
    print("Hello")
end

hello()

Output?

Hello

B) Nothing

C) Error

hello

✅ Answer: A

💡 hello() runs the function.

Q5

Which line calls a function?

function hello()

hello()

end

print = hello

✅ Answer: B

Q6

Can you call the same function 100 times?

A) No

B) Yes

C) Only twice

D) Only inside loops

✅ Answer: B

💡 That's the whole point!

🟡 LEVEL 2 — Think Like a Programmer

Q7

function greet()
    print("Welcome!")
end

greet()
greet()

Output?

Welcome!

Welcome!
Welcome!

C) Nothing

D) Error

✅ Answer: B

Q8

function jump()
    print("Jump!")
end

How many times does "Jump!" print?

A) 0

B) 1

C) 2

D) Infinite

✅ Answer: A

💡 The function is created but never called.

Q9

function attack()
    print("Hit!")
end

attack()
attack()
attack()

How many times is "Hit!" printed?

A) 1

B) 2

C) 3

D) 4

✅ Answer: C

Q10

function bye()
    print("Bye")
end

print("Start")
bye()

What prints first?

A) Bye

B) Start

C) Error

D) Nothing

✅ Answer: B

Q11

function test()
    print("Lua")
end

test()

print("Done")

What's printed last?

A) Lua

B) Done

C) test

D) Error

✅ Answer: B

Q12

Functions help reduce...

A) Bugs caused by copying code

B) Variables

C) Loops

D) Tables

✅ Answer: A

💡 Copy-paste code is one of the biggest sources of bugs.

🟠 LEVEL 3 — Real-Life Programming

Q13

Every time the player dies, you must:

Play sound
Show animation
Respawn player

Best approach?

A) Copy the code everywhere

B) Create playerDied()

C) Use a loop

D) Use if

✅ Answer: B

Q14

A website sends an email after every purchase.

Best design?

A) Write email code every time

B) Create sendEmail()

C) Use while

D) Store it in a variable

✅ Answer: B

Q15

You're making a calculator.

Which names make sense?

abc()

x()

addNumbers()

hello123()

✅ Answer: C

💡 Function names should describe what they do.

Q16

You want to play a button click sound everywhere.

Best approach?

A) Copy the sound code 50 times

B) Make playClickSound()

C) Use while

D) Use print

✅ Answer: B

Q17

Which is easier to read?

a()

x()

calculateTotalPrice()

zzz()

✅ Answer: C

Q18

You want to reuse the same logic in many places.

What's the best tool?

A) Variable

B) Function

C) Table

D) Boolean

✅ Answer: B

🔴 LEVEL 4 — Bug Hunter

Q19

function hello()
    print("Hi")

What's wrong?

A) Missing end

B) Missing if

C) Missing for

D) Nothing

✅ Answer: A

Q20

function hello()
    print("Hi")
end

Hello()

Problem?

A) Nothing

B) Lua ignores uppercase/lowercase

C) Function name doesn't match

D) Missing print

✅ Answer: C

💡 hello and Hello are different names.

Q21

function run()
    print("Running")
end

Why doesn't anything print?

A) Missing run()

B) Missing end

C) Missing while

D) Missing for

✅ Answer: A

Q22

function score()
    print("100")
end

score

Problem?

A) Nothing

B) Forgot ()

C) Missing end

D) Missing if

✅ Answer: B

💡 score refers to the function; score() runs it.

Q23

function hello()
    print("Hi")
end

hello()
hello()

How many times does it run?

A) 1

B) 2

C) 3

D) Infinite

✅ Answer: B

Q24

What's better?

function a()

function doStuff()

function updatePlayerHealth()

function xyz()

✅ Answer: C

💡 Clear names make code easier to understand months later.

🟣 LEVEL 5 — Boss Battle 👑

Q25

A function is best described as...

A) Memory

B) A custom command

C) A loop

D) A table

✅ Answer: B

Q26

Creating a function automatically runs it.

A) True

B) False

✅ Answer: B

💡 You must call it with ().

Q27

What does this print?

function dance()
    print("💃")
end

dance()
dance()
dance()

💃

💃💃

💃
💃
💃

D) Nothing

✅ Answer: C

Q28

Which is the biggest advantage of functions?

A) Faster internet

B) Reuse code

C) Create tables

D) Replace variables

✅ Answer: B

Q29

Which is the most professional function name?

a()

test123()

calculateDamage()

x()

✅ Answer: C

Q30 — Final Boss

If you find yourself copying the same 10 lines of code into 8 different places, what should your first thought be?

A) Keep copying

B) Make the code longer

C) Put those 10 lines inside a function

D) Create more variables

✅ Answer: C

💡 One of the biggest habits of good programmers is this:

If you're copying code, stop and ask: "Should this be a function?"

🧠 Pareto Cheat Sheet

Situation	Use
Create a function	`function name()`
End a function	`end`
Run a function	`name()`
Use functions for	Reusing code
Good function names	`calculateScore()`, `playSound()`, `spawnEnemy()`
Avoid	`a()`, `x()`, `test()` (unless it's truly a test)

🏆 Boss Tip

From now on, think of functions like the built-in commands you've already used:

print() → Built-in function.
math.random() → Built-in function.
tonumber() → Built-in function.

Now you're creating your own commands:

attackEnemy()
saveGame()
healPlayer()
openDoor()

That's a major step—from just using a programming language to extending it with your own reusable building blocks.