#include <iostream>
#include <stdexcept>
#include <cmath>
/**
* @brief Returns the N-th digit of a number counting from the right.
*
* Example:
* number = 12345
* position = 1 -> 5
* position = 2 -> 4
* position = 3 -> 3
*
* @param number The input number.
* @param position The digit position (1-based, from the right).
* @return int The digit at the specified position.
*
* @throws std::invalid_argument if position < 1.
*/
int getDigitFromRight(long long number, int position)
{
if (position < 1) {
throw std::invalid_argument("Position must be greater than 0.");
}
// Work with positive numbers only.
number = std::llabs(number);
// Shift the desired digit to the ones place.
for (int i = 1; i < position; ++i) {
number /= 10;
}
// Extract the last digit.
return static_cast<int>(number % 10);
}
int main()
{
long long number = 12345;
std::cout << getDigitFromRight(number, 1) << '\n'; // 5
std::cout << getDigitFromRight(number, 3) << '\n'; // 3
std::cout << getDigitFromRight(number, 5) << '\n'; // 1
return 0;
}
/*
run:
5
3
1
*/
