#include <stdio.h>
#include <math.h>

double f(double x) {
  return x * x * x - x - 2;
}

int main() {
  double a = 1, b = 2;
  for (int i = 1; i <= 20; i++) {
    double m = (a + b) / 2;
    double fm = f(m);
    printf("iter %2d: m = %.6f  f(m) = %.6f\n", i, m, fm);
    if (fm == 0) break;
    if (f(a) * fm < 0) b = m;
    else a = m;
  }
  return 0;
}