01-algorithmic_toolbox/01-intro/02-fibonacci_last_digit/fibonacci_last_digit.cpp


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#include <iostream>

int get_fibonacci_last_digit(int n) {
    int a, b, c, i;

    if (n <= 1)
        return n;

    a = 0; b = 1;
    for(i = 1; i < n; i++) {
        c = a + b;
        if (c >= 10)
            c -= 10;
        a = b;
        b = c;
    }
    if (b >= 10)
        b -= 10;

    return b;
}

int main() {
  int n;
  std::cin >> n;
  int c = get_fibonacci_last_digit(n);
  std::cout << c << '\n';
}