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🎯 Lesson 3

Functions: Code Recipes! 🍪📝

Write instructions once, use them again and again. Just like a recipe for your favorite cookies!

🤔 What is a Function?

A function is like a recipe. You write down the steps once, give it a name, and then you can use that recipe anytime!

🍪

Cookie Recipe = Function

📝 Write Recipe Once:

  1. Mix flour and sugar
  2. Add eggs and butter
  3. Add chocolate chips
  4. Bake at 350° for 12 min

🍪 Use Anytime!

Now whenever you want cookies, just say:

makeCookies()

🌍 Functions in Real Life

You use "functions" every day without realizing it!

🚿

"Take a Shower"

Many steps (get water, soap, rinse) but you just say "shower"!

🎮

"Press Start"

One button does LOTS of things to start the game!

📱

"Call Mom"

Phone does many things with just two words!

⚙️ How Functions Work

Making a function has two parts:

1

Create (Define) the Function

Write down all the steps and give it a name:

function sayHello ()
print "Hello there!"
print "Nice to meet you!"
2

Call (Use) the Function

Just say its name to make it run!

sayHello () // This runs all the steps!

Output:

Hello there!

Nice to meet you!

🎁 Functions Can Take Inputs!

You can give information TO a function, like putting ingredients into a recipe!

🍕 Pizza Function

function makePizza ( topping )
print "Making pizza with"
print topping

🎉 Using It!

makePizza("pepperoni")

→ Making pizza with pepperoni

makePizza("cheese")

→ Making pizza with cheese

makePizza("veggies")

→ Making pizza with veggies

🎁 Functions Can Give Back Results!

Some functions give you something back, like a vending machine giving you a snack!

💰

Put in: 2 + 3

➡️
🔧
add(2, 3)

Function does math

➡️
🎉
5

Get back: 5

🎮 Functions in Games!

Video games are FULL of functions!

⚔️

attack()

Swing sword, play sound, deal damage - all in one function!

🦘

jump()

Make character go up, play whoosh sound, then come back down!

💫

collectCoin()

Add to score, make coin disappear, play cha-ching!

💀

gameOver()

Stop game, show score, ask to play again!

💪 Why Are Functions Awesome?

📦

Stay Organized

Keep related code together in neat packages!

♻️

Reuse Code

Write once, use many times!

🐛

Fix Bugs Easier

Fix in one place, works everywhere!

🤝

Work Together

Teams can share and use each other's functions!

Remember This!

  • 1

    Functions are like recipes - write steps once, use anytime!

  • 2

    Give your function a name that describes what it does

  • 3

    Functions can take inputs (like ingredients)

  • 4

    Functions can give back results (like a vending machine)