Question

How to sum the digit of a factorial of a number in Kotlin

Answer 1

fun sumDigits(num: Long): Int {
    var sum = 0
    var n = num
    while (n != 0L) {
        sum += (n % 10).toInt()
        n /= 10
    }
    return sum
}

fun factorial(n: Long): Long {
    return if (n == 1L || n == 0L) 1 else n * factorial(n - 1)
}

fun main() {
    val number = 9L
    val result = factorial(number)

    println("factorial = $result")
    println("sum digits = ${sumDigits(result)}")
}


   
/*
run:

factorial = 362880
sum digits = 27
 
*/

 

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