include<stdio.h> include<math.h> int main(){ double a, b, c; while (~scanf("%lf%lf%lf", &a, &b, &c)) { double x1, x2; double date = b * b - 4 * a*c; if (a != 0) { if (b*b - 4 * a*c < 0)//我知道问题所在了,此时根号下是负数 { ...