一元二次方程：求一元二次方程〖ax〗^2+bx+c=0的解（a、b、c为任意实数）。

#include 
#include 

void main() {
    double a, b, c, disc, x1, x2, realpart, imagpart;
    scanf("%lf%lf%lf", &a, &b, &c);
    printf("The equation ");
    if (fabs(a) <= 1e-6)
        printf("is not a quadratic");
    else {
        disc = b * b - 4 * a * c;
        if (fabs(disc) <= 1e-6)
            printf("has two equal roots:%8.4f", -b / (2 * a));
        else if (disc > 1e-6) {
            x1 = (-b + sqrt(disc)) / (2 * a);
            x2 = (-b - sqrt(disc)) / (2 * a);
            printf("has two differ roots:%8.4f and %8.4f", x1, x2);
        } else {
            realpart = -b / (2 * a);
            imagpart = sqrt(-disc) / (2 * a);
            printf(" has complex roots:\n");
            printf("%8.4f+%8.4fi\n", realpart, imagpart);
            printf("%8.4f-%8.4fi\n", realpart, imagpart);
        }
    }
}