Kotlin Functions

fun greet() { # function without parameters
    println("Hello")
}

fun greet(name: String) { # function with parameter
    println("Hello, $name")
}

fun add(a: Int, b: Int): Int { # function with return type
    return a + b
}
fun multiply(a: Int, b: Int) = a * b # single-expression function

fun greet(name: String = "Guest") { # default parameter value
    println("Hello, $name")
}
greet() # uses default "Guest"

fun createUser(name: String, age: Int, city: String) { }
createUser(name = "John", age = 30, city = "NYC") # named args
createUser(age = 30, name = "John", city = "NYC") # any order

fun sum(vararg numbers: Int): Int { # variable number of args
    return numbers.sum()
}
sum(1, 2, 3, 4) # any number of arguments