到底錯在哪裡>  <"

#include<iostream>
#include<math.h>
using namespace std;

int main()
{
    int a,b,c,d,e,f;
   
    while (cin>>a>>b>>c)
    {
          d = sqrt(b*b-a*4*c);
          e = (-b+d)/2*a;
          f = (-b-d)/2*a;      
          if(b*b-4*a*c > 0)
          {
             if(e>f)
             cout<<"Two different roots x1="<<e<<" , x2="<<f<<endl;
             else if(f>e)
             cout<<"Two different roots x1="<<f<<" , x2="<<e<<endl;
          }
          else if(b*b-4*a*c == 0)
          {
             cout<<"Two same roots x="<<e<< endl;
          }
          else if (b*b-4*a*c < 0)
          {
             cout<<"No real root"<<endl;
          }
    }
   
    return 0;
}

*** 第 5 點 (20%)：WA (line:1)
您的答案為: Two same roots x=-4
正確答案為: Two same roots x=-1