Lesson 1

Kotlin Fundamentals: Understanding and Creating Functions

Introduction to Functions in Kotlin

Welcome aboard our Kotlin programming adventure! Today, we're delving into functions. In the coding universe, a function serves as a mini-program performing a particular task. It helps to partition more extensive programs into organized, reusable components. Envision functions as home robots, each responsible for a specific task.

Writing a Basic Function in Kotlin

To write a Kotlin function, we define its name and task using this syntax:

Kotlin
1fun functionName() { 2 // Code indicating the function's task 3}

Here, the keyword fun declares a function. Let's define a function named greet that extends a friendly message to the world:

Kotlin
1fun greet() { 2 println("Hello, World!") 3}

This function, named greet, prints "Hello, World!" to the console when invoked.

Invoking or Calling a Function in Kotlin

To execute its task, we "call" or "invoke" a function using its name followed by parentheses. Functions are often summoned within the special main function. The main function acts as the concertmaster of our program, steering when and which parts (functions) of our code perform.

Here's an example of main calling greet:

Kotlin
1fun greet() { 2 println("Hello, World!") 3} 4 5fun main() { 6 // Call the greet function 7 greet() // Prints "Hello, World!" 8}

When this program runs, main gets invoked first. Within main, we call greet(). This command triggers the greet function, which subsequently outputs Hello, World!.

Lesson Summary and Upcoming Exercises

Well done! We've acquired an understanding of how to write and invoke simple functions in Kotlin. In our forthcoming exercises, you'll get to pen and call your basic functions. This practice will reinforce what you've learned today. So, continue practicing, and let's venture further into the world of Kotlin!

Enjoy this lesson? Now it's time to practice with Cosmo!

Practice is how you turn knowledge into actual skills.