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))
    {
        if(0==a)printf("Not quadratic equation\n");
        else
        {
            if(0==b*b-4*a*c&&(-b)/(2*a)!=0)printf("x1=x2=%.2f\n",(-b)/(2*a));
            else if(0==b*b-4*a*c&&(-b)/(2*a)==0)printf("x1=x2=0.00\n");
            else if(b*b-4*a*c>0)printf("x1=%.2f;x2=%.2f\n",(-b-sqrt(b*b-4*a*c))/(2*a),(-b+sqrt(b*b-4*a*c))/(2*a));
            else printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n",-b/(2*a),sqrt(4*a*c-b*b)/(2*a),-b/(2*a),sqrt(4*a*c-b*b)/(2*a));
        }
    }
    return 0;
}