题解 | #计算一元二次方程#

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