#include "library.h"
#include <iomanip>

double power(const double x, const int n)
{ if (n == 0)
    return 1;
  return x * power(x, n - 1); }

double factorial(const double n)
{ if (n == 0)
    return 1;
  return n * factorial(n - 1); }

double sine(const double x, const int n, const int sign)
{ if (n > 70)
    return 0;
  return sign * power(x, n) / factorial(n) + sine(x, n + 2, - sign); }

double sine(const double x)
{ return sine(x, 1, +1); }

void main()
{ cout << "Enter x: ";
  const double x = read_double();
  cout << setprecision(15) << sine(x) << "\n";
  cout << setprecision(15) << sin(x) << "\n";
  main(); }