Lesson 3 of 5 · 15–25 minutes

Functions

🏠The everyday picture

A recipe card titled "Masala chai". Once written, you don't re-explain the steps each time; you say "make masala chai", and anyone can follow it. A function is a named recipe in code.

📘What it really is

A function is a named block of code you can run (call) whenever you need it:

function greet() {
  console.log("Welcome to Tutor Workstation");
}

greet();
greet();

Defining a function doesn't run it; calling it with () does.
Why functions matter:
reuse: write once, use many times;
names explain intent: calculateFee() says what the code is for;
small pieces are easier to understand, test and fix.
A good function does one clear job and is named with a verb: showMenu, checkForm, calculateTotal.
When reading AI code, start with the function names. They're the table of contents.

🖱️Try it

Move your level-finding code from Lesson 1 into a function called showLevel. Call it three times. Notice that you can't yet tell it which number to use; that's the next lesson.

✅Quick check

You write a function but nothing happens. What did you probably forget?

Show the answer

To call it, with its name followed by ().

Why is calculateTotal a better function name than doStuff?

Show the answer

It says what the function does, so code that uses it reads clearly.