reverse string kotlin

fun main() {
    val str = "Hello, world!"
    val reversed = reverseString(str)
    println("Original: $str")
    println("Reversed: $reversed")
}

fun reverseString(str: String): String {
    var reversed = ""
    for (i in str.length - 1 downTo 0) {
        reversed += str[i]
    }
    return reversed
}