/*
 * Program to calculate roots of a quadratic equation using
 * the quadratic formula.  For now, input is hard-coded.
 */
#include <stdio.h>
#include <math.h>

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

int main(void) {
        solve_and_print(1, 0, -4);
        solve_and_print(1, 0, 4);
        solve_and_print(1, 0, 0);
        solve_and_print(0, 1, 4); 
        solve_and_print(0, 0, 4); 
        solve_and_print(0, 0, 0); 
        return 0;
}

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

        double discrim;

	printf("for equation with coefficients %g, %g, %g:\n",
			a, b, c);
       
	if (a == 0) {
		if (b != 0) {
			printf("one root:  %g\n", c/b);
		}
		else if (c != 0) {
			printf("no roots\n");
		}
		else {
			printf("all numbers are roots\n");
		}
	}
	else {
		discrim = b*b - 4*a*c;

		if (discrim > 0) {
			printf("two roots:  %g %g\n", 
					(-b + sqrt(discrim))/(2*a),
					(-b - sqrt(discrim))/(2*a));
		}
		else if (discrim == 0) {
			printf("one root:  %g\n", (-b) / (2*a));
		}
		else {
			printf("no roots\n");
		}
	}
}