Parameters

A function can have zero or more parameters. Our function, basicFunction, takes two parameters, as shown in the following code:

fun basicFunction(name: String, size: Int) {

}

Each parameter is defined as parameterName: ParameterType, in our example, name: String and size: Int. Nothing new here.

vararg

It gets interesting when parameters have two types that we have already covered—vararg and lambdas:

fun aVarargFun(vararg names: String) {
   names.forEach(::println)
}

fun main(args: Array<String>) {
   aVarargFun()
   aVarargFun("Angela", "Brenda", "Caroline")
}

A function with a parameter marked with the modifier, vararg can be called with zero or more values:

fun multipleVarargs(vararg names: String, vararg sizes: Int) {
// Compilation error, "Multiple vararg-parameters are prohibited"
}

A function can't have multiple vararg parameters, not even with different types.

Lambda

We already discussed how, if a function's last parameter is a lambda, it can't be passed outside the parenthesis...