For counting vowel in a string by Recursive method.

VowelsCountRecursive.kt

var count = 0
fun main(args: Array<String>) {
    println("Enter string to Count Vowels: ")
    val inputSt: String? = readLine()!!
//    val inputSt: String? = "Hi this to check"
    print(checkforVowel(inputSt, inputSt?.length))
}

fun checkforVowel(inputSt: String?, length: Int?): Int {
    if (length == 1){
       return isVowel(inputSt?.toCharArray()?.get(length.minus(1)))
    }
    else return checkforVowel(inputSt, length!!.minus(1)) + isVowel(inputSt?.toCharArray()?.get(length.minus(1)))
}

fun isVowel(ch:Char?): Int {
    val checkVowel = ch?.toUpperCase()
    if (checkVowel == 'A' || checkVowel == 'E' || checkVowel == 'I' || checkVowel == 'O' || checkVowel == 'U'){
//        count += 1
        return 1
    } else return 0
}