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

#define EPS 1.0e-6

double f(double x) {
  // f(x) = e^x + 2x - 5
  return exp(x) + 2.0*x - 5.0;
}

int main(void) {
  double a = 0.0, b = 3.39;
  
  while (fabs(b - a) > EPS) {
    double c = (a + b) / 2.0;
    if (f(c)*f(a) > 0) {
      // f(a) in f(c) imata isti predznak
      a = c;
    } else {
      b = c;
    }
  }
  
  printf("x = %lf\n", a);
  return 0;
}