题解 | #计算一元二次方程#

``#include<stdio.h>
#include<math.h>
int main()
{
double a = 0;
double b = 0;
double c = 0;
   while( scanf("%lf%lf%lf",&a,&b,&c) != EOF)
   {
    if(a == 0)    
        printf("Not quadratic equation");    
    else
     {
       double d = b*b-4*a*c;
        if(d == 0)
        {
            double x1 = (-b+sqrt(d))/(2*a) ;
            printf("x1=x2=%.2lf\n",x1);
        }
        else if(d > 0)
        {
            double x1 = (-b-sqrt(d))/(2*a);
            double x2 = (-b+sqrt(d))/(2*a);
            printf("x1=%.2lf;x2=%.2lf\n",x1,x2);
        }
        else if(d < 0)
        {
             double x1 = (-b)/(2*a);
            double X1  =(sqrt(-d))/(2*a);
            double x2  =(-b)/(2*a);
            printf("x1=%.2lf-%.2lfi;x2=%.2lf+%.2lfi\n",x1,X1,x2,X1);
        }
     }
   }
    return 0;
}