Exponenta

#include <cstdio>

//exp(x) evaluation
int main() {
  double x = -1000;

  bool invert = (x < 0);
  if (invert) {
    x = -x;
  }
  double res = 0;

  double pw = 1;
  double fac = 1;
  for (int i = 0; i < 100; ++i) {
    res += pw/fac;
    fac *= (i+1);
    pw *= x;
  }

  if (invert) {
    res = 1 / res;
    x = -x;
  }

  printf("exp(%lf) = %lf\n", x, res);

  return 0;
}