>>729
#include <stdio.h>
void quad(double a, double b, double c)
{
double d = b*b-4*a*c;

printf("a = %5.2lf, b = %5.2lf, c = %4.2lf\n", a, b, c);
if (d > 0) {
printf("実数解 : x1 = %5.2lf, x2 = %5.2lf\n",
(-b+sqrt(d))/(2*a),
(-b-sqrt(d))/(2*a)
);
} else if (d == 0) {
printf("重解 : x = %5.2lf\n", -b/(2*a));
} else {
printf("虚数解 : 実数部 = %5.2lf, 虚数部 = %5.2lf\n",
-b/(2*a), sqrt(-d)/(2*a));
}
}
int main(void)
{
double a,b,c;
puts("２次方程式の３つの係数を入力してください");
while (scanf("%lf %lf %lf", &a, &b, &c) != EOF) {
if (a == 0) { puts("係数 a は 0 意外でなければなりません"); continue; }
quad(a, b, c);
}
return 0;
}