#include <iostream>
// Finds the digit that comes before the target digit when scanning from right to left.
int findPreviousDigit(int number, int target) {
int previous = -1;
int current;
while (number > 0) {
current = number % 10;
number /= 10;
if (current == target) {
if (number != 0) {
return number % 10;
}
}
previous = current;
}
return -1;
}
int main() {
int number = 8902741;
int target = 7;
int result = findPreviousDigit(number, target);
if (result != -1) {
std::cout << "The digit before " << target << " in " << number << " is " << result << ".\n";
} else {
std::cout << "The digit " << target << " is not found or has no previous digit in " << number << ".\n";
}
}
/*
run:
The digit before 7 in 8902741 is 2.
*/
