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

/* Hungarian notation - abbreviated type names attached to all variables */
void solve_quadratic_equation(double d_a, double d_b, double d_c, 
                              int *pi_number_of_roots, double *pd_root1, 
                              double *pd_root2){
  double d_discriminant;

  d_discriminant = d_b * d_b - 4 * d_a * d_c;

  if (d_discriminant < 0){
    *pi_number_of_roots = 0;
  }
  else if (d_discriminant == 0){
    *pi_number_of_roots = 1;
    *pd_root1 = -d_b/(2*d_a);
  }
  else{
    *pi_number_of_roots = 2;
    *pd_root1 = (-d_b + sqrt(d_discriminant))/(2*d_a);
    *pd_root2 = (-d_b - sqrt(d_discriminant))/(2*d_a);
  }
}   

int main(void) {
  double d_a, d_b, d_c, d_firstRoot, d_secondRoot;
  int i_number_of_roots;
  printf("Enter coeficients a, b, and c: ");
  scanf("%lf %lf %lf", &d_a, &d_b, &d_c);

  if (d_a != 0){
    solve_quadratic_equation(d_a, d_b, d_c, 
             &i_number_of_roots, &d_firstRoot, &d_secondRoot);  
    if (i_number_of_roots == 0)
      printf("No roots\n");
    else if (i_number_of_roots == 1)
      printf("One root: %f\n", d_firstRoot);
    else 
      printf("Two roots: %f and %f\n", d_firstRoot, d_secondRoot);
  }
  else
    printf("The coeficient a must be non-zero");

  return 0;
}