/**
* Finds the digit that comes before the target digit when scanning from right to left.
*
* return The digit that comes before the target, or -1 if not found or no previous digit.
*/
fun findPreviousDigit(number: Int, target: Int): Int {
var num = number
while (num > 0) {
val current = num % 10
num /= 10
if (current == target) {
return if (num > 0) num % 10 else -1
}
}
return -1
}
fun main() {
val number = 8902741
val target = 7
val result = findPreviousDigit(number, target)
if (result != -1) {
println("The digit before $target in $number is $result.")
} else {
println("The digit $target is not found or has no previous digit in $number.")
}
}
/*
run:
The digit before 7 in 8902741 is 2.
*/
