Anyone to help me figure out why the second function is not working

Question

https://code.sololearn.com/clBjc6TOP3bj/?ref=app

Answer 1

bernard

String should be inside double quotes ""

And why there is $ before variable name? firstname and lastname

fun main(args: Array<String>) {
println(add(5,7))
println(fullname("Bernard", "Ocran"))
}

fun add(num1: Int,num2: Int): Int{
return(num1.plus(num2))
}

fun fullname(firstname: String, lastname: String): String{
return (firstname + lastname)
}

Answer 2

A͢J thanks