Kotlin

Hello World in Kotlin

Every programming journey starts with Hello World. Let’s write our first Kotlin program.

The Code

Create a file named Hello.kt:

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fun main() {
    println("Hello, World!")
} …

Variables and Types in Kotlin

Kotlin’s type system is one of its defining features. It combines the safety of static typing with the convenience of type inference, so you rarely need to write explicit type annotations while …

Operators in Kotlin

Operators are the building blocks of expressions in any programming language. Kotlin provides a rich set of operators that go beyond the standard arithmetic and logical operators you’d expect …

Control Flow in Kotlin

Control flow is how a program decides what to do next: which branch to take, which block to repeat, and when to stop. Kotlin keeps the familiar if, for, and while from Java but reshapes them around …

Functions in Kotlin

Functions are the building blocks of any Kotlin program. They let you package logic into reusable, named units, give it clear inputs and outputs, and compose larger programs out of small, testable …

Channels, Actors, and Goroutines: The Concurrency Models That Divided Language Design

In 1973, Carl Hewitt published a paper describing something he called the Actor model — isolated computational units that communicated exclusively by message passing, with no shared memory, no locks, …

The Billion-Dollar Mistake, 60 Years Later: How Languages Handle Null

In 2009, Tony Hoare stood at the QCon conference in London and confessed to a crime.

“I call it my billion-dollar mistake,” he said. “It was the invention of the null reference in …

def, func, fun, fn, sub: Why Every Language Has a Different Word for the Same Thing

Open almost any programming language reference and you will find, somewhere near the beginning, a section explaining how to define a reusable named block of code. The concept is universal. The word …

How 10 New Programming Languages Are Rewriting the Rules (And Why They Were Born)

Every programming language is, at its core, a written argument. An argument that the languages which came before failed at something important — something worth spending years of your life to fix. …