Kotlin is a statically-typed programming language that runs on the Java Virtual Machine (JVM). It is designed to be concise, expressive, and safe, making it a popular choice for Android app development, server-side programming, and web development.
Variables in Kotlin are declared using the var or val keyword. Kotlin supports type inference, so you don’t need to specify the type of the variable.
var name = "John"
val age = 30
val pi = 3.14
Functions in Kotlin are declared using the fun keyword followed by the function name and parameters. Kotlin supports lambda expressions, which are anonymous functions that can be assigned to variables and passed as arguments to other functions.
fun greet(name: String) {
println("Hello, $name!")
}
greet("John")
val add = { a: Int, b: Int ->
a + b
}
println(add(2, 3))
Kotlin supports for and while loops, as well as the enhanced for loop, which can iterate over collections.
val numbers = listOf(1, 2, 3, 4, 5)
for (number in numbers) {
println(number)
}
var i = 0
while (i < 5) {
println(i)
i++
}
Kotlin supports if, else if, and else statements, as well as the ternary operator.
val age = 30
if (age < 18) {
println("You are too young to vote.")
} else if (age < 21) {
println("You can vote, but not drink.")
} else {
println("You can vote and drink.")
}
val result = if (age >= 18) "You are an adult" else "You are not an adult"
println(result)
Kotlin provides several ways to read and write files. You can use the File class to create, read, write, and delete files.
val file = File("example.txt")
// Write to file
file.writeText("Hello, world!")
// Read from file
val content = file.readText()
println(content)
// Delete file
file.delete()