题解 | #计算一元二次方程#

#include <stdio.h>
#include<math.h>
int main()
{
    float a,b,c;
    float x1 = 0;
    float x2 = 0;
    while(~scanf("%f %f %f", &a, &b, &c))
    {
        if(a == 0)
        {
            printf("Not quadratic equation\n");
        }
        else
        {
            float k = (b * b) - (4* a * c);
            if(k == 0)
            {
                float mp = (-b) + sqrt(k);
                if(mp == 0)
                {
                    x1 = 0;
                     printf("x1=x2=%.2f\n",x1);
                }
                else
                {
                    x1 = mp / 2.0 / a;
                    printf("x1=x2=%.2f\n",x1);
                }
            }
            else if(k > 0)
            {
                x1 = ((-b) - sqrt(k)) / 2.0 / a;
                x2 = ((-b) + sqrt(k)) / 2.0 / a;
                printf("x1=%.2f;x2=%.2f",x1,x2);
            }
            else
            {
                float m,n;
                m = -b / 2.0 / a;
                n = sqrt(-k) / 2.0 / a;
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi",m,n,m,n);
            }
        }
    }
    return 0;
}