#include <stdio.h>

int resoudreEquationSecondDegre(double a, double b, double c, double* x1, double* x2) {
  double delta = b * b - 4.0 * a * c;
  if (delta < 0.0) {
    return 0;
  }
  else {
    if (delta == 0.0) {
      *x1 = -b / (2.0 * a);
      return 1;
    }
    else {
      *x1 = (-b - sqrt(delta)) / (2.0 * a);
      *x2 = (-b + sqrt(delta)) / (2.0 * a);
      return 2;
    }
  }
}

void tester(double a, double b, double c) {
  double x1;
  double x2;
  int nb = resoudreEquationSecondDegre(a, b, c, &x1, &x2);
  switch (nb) {
    case 0: {
      printf("L'equation %.3lfx2%+.3lfx%+.3lf n'a pas de racine reelle\n", a, b, c);
    }
    break;
    case 1: {
      printf("L'equation %.3lfx2%+.3lfx%+.3lf a une racine reelle : %lf\n", a, b, c, x1);
    }
    break;
    case 2: {
      printf("L'equation %.3lfx2%+.3lfx%+.3lf a deux racines reelles : %lf et %lf\n", a, b, c, x1, x2);
    }
    break;
  }
}

int main(void) {
  tester(2.0, -3.1, 2.1);
  tester(2.0, 4.0, 2.0);
  tester(-2.0, 5.0, -2.0);
  return 0;
}