/* p2_2r.c */
#include <stdio.h>
#include <math.h>

int ratkaise_2_asteen_yhtalo(double *x1, double *x2,
  double a, double b, double c)
{
  double D,SD;
  *x1 = *x2 = 0;
  if ( a==0 ) {
    if ( b==0 ) {
      if ( c==0 ) return 0;
      return 1;
    }
    *x1 = *x2 = -c/b;
    return 0;
  }
  D = b*b - 4*a*c;
  if ( D>=0 ) {
    SD  = sqrt(D);
    *x1 = (-b-SD)/(2*a);
    *x2 = (-b+SD)/(2*a);
    return 0;
  }
  return 1;
}

double P2(double x, double a, double b, double c)
{
  return (a*x*x + b*x + c);
}

int main(void)
{
  double a,b,c,x1,x2;
  do {
    printf("Anna 2. asteen yht„l”n a b c >");
    scanf("%lf %lf %lf",&a,&b,&c);
    if ( ratkaise_2_asteen_yhtalo(&x1,&x2,a,b,c) ) {
      printf("Yht„l”ll„ ei ole reaalisia juuria!\n");
    }
    else {
      printf("1. ratkaisu on %lf.  "
             "Arvoksi tulee t„ll”in %lf.\n",x1,P2(x1,a,b,c));
      printf("2. ratkaisu on %lf.  "
             "Arvoksi tulee t„ll”in %lf.\n",x2,P2(x2,a,b,c));
    }
  } while (a>0);
  return 0;
}