/*
 * Program to calculate solutions (roots) of a quadratic equation
 *
 *   a*x*x + b*x + c = 0
 * 
 * using the quadratic formula.
 * 
 * Input:  Floating-point numbers a, b, and c (coefficients of
 *   equation).
 *
 * Output:  Solution(s) of the equation, if they exist, or a message saying
 *   that there are none.
 */
#include <stdio.h>
#include <math.h>	/* needed for sqrt() function */

int main(void) {

	float a;
	float b;
	float c;
	float discrim; /* discriminant -- b*b - 4*a*c */

	printf("enter coefficients (a, b, c):\n");
	scanf("%f", &a);
	scanf("%f", &b);
	scanf("%f", &c);
	printf("Solutions for %g * x*x + %g * x + %g = 0:\n", a, b, c);

	/* first check for a == 0 */
	if (a == 0) {
		if (b == 0) {
			if (c == 0) {
				printf("(any number)\n");
			}
			else {
				printf("(none)\n");
			}
		}
		else {
			printf("%g\n", -c / b);
		}
	}
	else {

		/* compute discriminant */
		discrim = (b*b) - (4*a*c);

		/* if negative, no solutions */
		if (discrim < 0) {
			printf("(none)\n");
		}

		/* if zero, one solution */
		else if (discrim == 0) {
			printf("%g\n", -b / (2*a) );
		}

		/* if positive, two answers */
		else { /* if we get here, we know discrim > 0 */
			printf("%g\n", (-b + sqrt(discrim)) / (2 * a) );
			printf("%g\n", (-b - sqrt(discrim)) / (2 * a) );
		}
	}

	return 0;
}