## 标题: 求一元二次方程的根(25分)

#include <stdio.h>
#include <math.h>
int  main (void)
{     double a,b,c,d,e,x1,x2;   
  scanf("%lf %lf %lf",&a,&b,&c);  
     d=b*b-4*a*c;  
      if (d>0)  
      {     if(a==0)     
           x1=-c/b;printf("%.2lf\n",x1);    
             if (a!=0)    
                 {   x1=(-b+sqrt(d))/(2*a);       
                      x2=(-b-sqrt(d))/(2*a);            
                      printf("%.2lf\n%.2lf\n",x1,x2);    
                 }   
      }   
      else if (d==0)  
      {     if (a==0&&b==0&&c==0)     
               printf("Zero Equation\n");   
              else if(a==0&&b==0&&c!=0)   
                  printf("Not An Equation\n");     
              else     
                     {  
                             x1=-b/(2*a);     
                        printf("%.2lf\n",x1);
                     }   
        }   
        else  
           {   if (a!=0)        
                  if(b==0)       
                     {
                                x1=sqrt(-d)/(2*a);         
                      x2=sqrt(-d)/(2*a);            
                      printf("0.00+%.2lfi\n0.00-%.2lfi\n",x1,x2); 
                }                                                                               
                    else        
                      {
                                  x1=sqrt(-d)/(2*a);       
                        e=-b/(2*a);        
                        x2=sqrt(-d)/(2*a);                
                        printf("%.2lf+%.2lfi\n%.2lf-%.2lfi\n",e,x1,e,x2);   
                                                
                       }  
            }
    return 0;
}