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

int main ()
{
    double a, b, c, D, s;

    printf("Enter a, b, c: "); scanf("%lf%lf%lf", &a,&b,&c);
    if (a == 0) {
        printf("I cannot proceed\n");
        return 1;
    }
    D = b * b - 4 * a * c;
    if (D == 0) {
        printf("One real root %lf", -b / (2 * a));
    } else if (D > 0) {
        s = sqrt(D);
        printf("Two real roots %lf and %lf\n",
                (-b+s)/(2*a), (-b-s)/(2*a));
    } else {
        s = sqrt(-D);
        printf("Two complex roots %lf + i %lf and %lf - i %lf\n",
                -b/(2*a), s/(2*a), -b/(2*a), s/(2*a));
    }
    return 0;
}