/*racines des polynomes de second degré
  eqn:  ax^2 + bx + c = 0
  racines: x = (-b +/- sqrt(b^2 - 4ac))/2a */   
#include <iostream>
#include <cmath>

using namespace std;

int main() {
  double a, b, c;
  cout << "Entrez les coefficients de l'equation :\n";
  cin >> a >> b >> c;
  
  if (a != 0.) { 
    double delta;
    delta = b*b - 4.*a*c;
    if (delta < 0.)
      cout << "Il n'y a pas des solutions reelles !" << endl;
    else if (delta == 0.) {
      double x;
      x = -b/(2.*a);
      cout << "Il y a deux solutions identiques : " << x << endl;
    }
    else { //delta > 0.
      double x1, x2;
      x1 = (-b + sqrt(delta)) / (2.*a);
      x2 = (-b - sqrt(delta)) / (2.*a);
      cout << "Les solutions sont x1 = " << x1 << " et x2 = " << x2 << endl; 
    } 
  }   
  else {   //a = 0
    cout << "a est nul, il s'agit d'une equation de 1ere degree !\n";
    cout << "La solution est " << -c/b << endl;
  }

  return 0;
}