/*
 * Program to find roots of a quadratic equation.
 * No input for now -- input is hardcoded.
 */
#include <stdio.h>
#include <math.h>

void find_roots(double a, double b, double c);


int main(void) {
    find_roots(1.0, 0.0, 0.0);
    find_roots(1.0, 0.0, -1.0);
    find_roots(1.0, 0.0, 1.0);	
    find_roots(1.0, -5.0, 6.0);	/* (x - 2)(x - 3) */
    find_roots(2.0, -7.0, 3.0);	/* (2x - 1)(x - 3) */
    find_roots(0.0, 1.0, 2.0);
    find_roots(0.0, 0.0, 1.0);
    find_roots(0.0, 0.0, 0.0);
    return 0;
}

/* print root(s) of a*x*x + b*x + c = 0, or message if none */
void find_roots(double a, double b, double c) {

    double discriminant = b*b - 4*a*c;

    printf("\na = %g, b = %g, c = %g\n", a, b, c);

    if (a == 0) {
        if (b == 0) {
            if (c == 0) {
                printf("everything is an answer!\n");
            }
            else {
                printf("there are no answers\n");
            }
        }
        else {
            printf("the answer is %g\n", -c / b);
        }
    }
    else if (discriminant > 0) {
        printf("the answers are %g %g\n",
                (-b + sqrt(discriminant)) / (2*a),
                (-b - sqrt(discriminant)) / (2*a));
    }
    else if (discriminant == 0) {
        printf("the answer is %g\n", -b / (2*a));
    }
    else {
        printf("there are no answers\n");
    }
}