Quadratic Equation

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
double a,b,c,d,D1,e,f,l;
double D;
int x1,x2;
cout<<"made by Y.Strike\n";
cout<<"vavedi a\n";
cin>>a;
cout<<"vavedi b\n";
cin>>b;
cout<<"vavedi c\n";
cin>>c;
if(a<=0)
{
d=a*(-1);
e=b*(-1);
f=c*(-1);
D=(e*e)-(4*d*f);
}
else
{
D=(b*b)-(4*a*c);
}
if(D<=0)
{
cout<<"nqma koreni(diskriminanta po malko ot 0)\n";
system("pause");
return 0;
}
else
l=sqrt(D);
x1=(-b+l)/(2*a);
x2=(-b-l)/(2*a);
if(x1==0)
{
    cout<<"uravnenieto ima samo edin koreen  X2="<<x2<<endl;
    system("pause");
    return 0;
}
else
{
    cout<<"  X1="<<x1<<"  X2="<<x2<<endl;
    system("pause");
return 0;
}
system("pause");
return 0;
}