using System;
class DigitFinder
{
// Finds the digit that comes before the target digit when scanning from right to left.
public static int FindPreviousDigit(int number, int target) {
while (number > 0) {
int current = number % 10;
number /= 10;
if (current == target) {
return number > 0 ? number % 10 : -1;
}
}
return -1;
}
static void Main()
{
int number = 8902741;
int target = 7;
int result = FindPreviousDigit(number, target);
if (result != -1) {
Console.WriteLine($"The digit before {target} in {number} is {result}.");
}
else {
Console.WriteLine($"The digit {target} is not found or has no previous digit in {number}.");
}
}
}
/*
run:
The digit before 7 in 8902741 is 2.
*/
