/*
 * Program to compute and print real roots of a*x**2 + b*x + c = 0
 * (** denotes exponentiation)
 *
 * Version that puts code in a function and calls it with some tests /
 * examples first.
 */
#include <stdio.h>
#include <math.h>

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

int main(void) {
	compute_roots(1, -1, -6);
	compute_roots(1, 0, 4);
	compute_roots(0, 5, 2);
	compute_roots(0, 0, 0);
	compute_roots(0, 0, 5);

	printf("\nenter three coefficients\n");
	double a, b, c;
	if (scanf("%lf %lf %lf", &a, &b, &c) != 3) {
		printf("need three numbers\n");
	} 
	compute_roots(a, b, c);
	return 0;
}
void compute_roots(double a, double b, double c) {
	double root1, root2;
	printf("coefficient a = %f, b = %f, c = %f\n", a, b, c);
	if (a == 0) {
		if (b == 0) {
			if (c != 0) {
				printf("no roots\n");
			}
			else {
				printf("all x's are roots\n");
			}
		}
		else {
			printf("one root %f\n", -c/b);
		}
	}
	else {
		double d = b*b - 4*a*c;
		if (d < 0) {
			printf("no real roots\n");
		} 
		else {
			root1 = (-b + sqrt(d)) / (2*a);
			root2 = (-b - sqrt(d)) / (2*a);
			printf("roots are %f, %f\n", root1, root2);
		}
	}
}