Declare A Function

A function is a reusable block of code that performs a specific task. Instead of writing the same code multiple times, you define it once in a function and call it whenever needed.

In Kotlin, you declare a function using the fun keyword, followed by the function name and parentheses:

fun greet() {
    println("Hello!")
}

fun main() {
    greet()
    greet()
}
// Output:
// Hello!
// Hello!

The function greet contains one line of code, but we can call it as many times as we want. The code inside the function only runs when we call it by writing its name followed by parentheses.

Functions help organize your code into logical pieces. Each function should do one specific thing, making your program easier to read and maintain. You've actually been using a function all along: main() is the special function where your program starts executing.