kotlin format number

fun main() {
    val number = 1234567890
    val formattedNumber = formatNumber(number)
    println("Formatted Number: $formattedNumber")
}

fun formatNumber(number: Int): String {
    val numberString = number.toString()
    val formattedStringBuilder = StringBuilder()

    var count = 0
    for (i in numberString.length - 1 downTo 0) {
        formattedStringBuilder.append(numberString[i])
        count++
        if (count == 3 && i > 0) {
            formattedStringBuilder.append(',')
            count = 0
        }
    }

    return formattedStringBuilder.reverse().toString()
}