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Module 3~9 min

Introduction to Functions

Functions let you package a set of instructions so they can be reused wherever needed, instead of rewriting them every time.

What You'll Learn

  • What a function is
  • Why functions are useful
  • A simple example of calling a function

What a Function Is

A function is a named, reusable block of code that performs a specific task. Once defined, it can be "called" -- run -- as many times as needed, from anywhere in the program.

Why Functions Help

Functions make code more organized and easier to maintain: fixing a bug inside a function fixes it everywhere that function is used, instead of needing to fix the same mistake in many places.

Example

A function named `calculateTotal` might be defined once, then called every time a total needs to be calculated throughout a program.

Key Concepts

FunctionReusabilityCalling a Function

Key Takeaways

  • A function is a named, reusable block of code
  • Functions can be called (run) from anywhere they're needed
  • Functions make code easier to organize and maintain

Knowledge Check

What is a key benefit of using functions?

What is a key benefit of using functions?