// Simply run g++ sample.cpp -lgmp to compile
#include <cstdio>
#include <gmp.h>
#define PRECISION 1024

int main() {
  unsigned long n = 1000000000000000000;
  mpf_t result, r, s, root5;

  mpf_init2(root5, PRECISION);
  mpf_sqrt_ui(root5, 5);

  mpf_init2(r, PRECISION);
  mpf_add_ui(r, root5, 1);
  mpf_div_2exp(r, r, 1);
  mpf_pow_ui(r, r, n);

  mpf_init2(s, PRECISION);
  mpf_ui_sub(s, 1, root5);
  mpf_div_2exp(s, s, 1);
  mpf_pow_ui(s, s, n);

  mpf_init2(result, PRECISION);
  mpf_sub(result, r, s);
  mpf_div(result, result, root5);

  mpf_out_str(stdout, 10, 10, result);

  putchar('\n');

  mpf_out_str(stdout, 10, 50, result);

  putchar('\n');

  mpf_out_str(stdout, 10, 100, result);

  return 0;
}