Kotlin Basic Syntax: A Comprehensive Tutorial with Code Examples

Kotlin Basic Syntax Tutorial

Kotlin is a modern programming language that runs on the Java Virtual Machine (JVM) and can also be compiled to JavaScript or native code. It’s known for its concise syntax, interoperability with Java, and strong type inference. In this tutorial, we’ll cover the basic syntax of Kotlin with code examples to help you get started.

1. Variables and Data Types

In Kotlin, variable declaration follows the pattern val or var followed by the name of the variable and its type (optional if it can be inferred).

// Immutable variable (read-only)
val name: String = "John"

// Mutable variable
var age: Int = 30

Kotlin provides a rich set of data types, including Int, Long, Double, Float, Boolean, Char, String, and more.

2. Functions

Functions in Kotlin are declared using the fun keyword. They can take parameters and return values.

fun add(a: Int, b: Int): Int {
    return a + b
}

// Function with inferred return type
fun multiply(a: Int, b: Int) = a * b

3. Control Flow

Kotlin supports standard control flow structures like if, else, for, while, and when.

val x = 10
val y = 5

if (x > y) {
    println("x is greater than y")
} else {
    println("y is greater than or equal to x")
}

for (i in 1..5) {
    println(i)
}

when (x) {
    1 -> println("x is 1")
    2 -> println("x is 2")
    else -> println("x is neither 1 nor 2")
}

4. Nullable Types

In Kotlin, types cannot have a value of null by default. If you need a variable to be nullable, you can declare its type followed by a question mark ?.

var nullableString: String? = null

5. String Templates

Kotlin supports string templates, allowing you to embed expressions directly in strings.

val name = "Alice"
val greeting = "Hello, $name!"
println(greeting) // Output: Hello, Alice!

Conclusion

This tutorial covered the basic syntax of Kotlin, including variables, data types, functions, control flow, nullable types, and string templates. With this foundation, you’re well-equipped to start writing Kotlin code. Experiment with these concepts and explore more advanced features to become proficient in Kotlin programming.