题解 | #计算一元二次方程#

#include <stdio.h>
#include <math.h>
int main()
{
    float a, b, c;
    while (scanf("%f %f %f", &a, &b, &c) != EOF)
    {
        float n;
        float x1, x2, p;
        n = (b * b) - (4 * a * c);
        if (a == 0)
        {
            printf("Not quadratic equation\n");
        }
        else if (a != 0 && b != 0 && c != 0)
        {
            if (n == 0)
            {
                x1 =(-b)/(2*a);
                x2 = x1;
                printf("x1=x2=%.2f\n", x1);
            }
            else if (n > 0)
            {
                x1 = ((-b) - sqrt(n)) / (2 * a);
                x2 = ((-b) + sqrt(n))/ (2 * a);
                printf("x1=%.2f;x2=%.2f\n", x1, x2);
            }
            else
            {

                p = (sqrt(-n)) / (2 * a);
                x1 = (-b / (2 * a));
                x2 = (-b / (2 * a));
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n",x1,p,x2,p);
            }
        }
        else
        {
            x1 = 0.00;
            x2 = x1;
            printf("x1=x2=%.2f\n", x1);
        }
    }
    return 0;
}