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

int main(void) {
  int i = 3;
  double a, b, c, discriminant;

  /* ... */

  /* Solve three equations:   */
  for (i = 1; i <= 3; i++){
    printf("Enter coeficients a, b, and c: ");
    scanf("%lf %lf %lf", &a, &b, &c);
  
    discriminant = b * b - 4 * a * c;
  
    if (discriminant < 0)
      printf("No roots\n");
    else if (discriminant == 0)
      printf("One root: %f\n", -b/(2*a));
    else 
      printf("Two roots: %f and %f\n",
             (-b + sqrt(discriminant))/(2*a), 
             (-b - sqrt(discriminant))/(2*a) );
  }

  /* ... */

  return 0;
}