下面是我写的代码，求指点错误。
#include<iostream>
using namespace std;
class dlbcomplex
{public:
    dlbcomplex(){real=0;imag=0;}
    dlbcomplex(int r,int i):real(r),imag(i){}
    dlbcomplex operator +(dlbcomplex &);
    dlbcomplex operator -(dlbcomplex &);
    friend istream& operator >>(istream&,dlbcomplex&);
    void display();
private:
    int real;
    int imag;
};
dlbcomplex dlbcomplex::operator +(dlbcomplex &c2)
{return dlbcomplex(real+c2.real,imag+c2.imag);
}
dlbcomplex dlbcomplex::operator -(dlbcomplex &c2)
{return dlbcomplex(real-c2.real,imag-c2.imag);
}
void dlbcomplex::display()
{
    cout<<real<<"+"<<imag<<endl;
}
istream& operator >>(istream &input,dlbcomplex &c3)
{
    input<<c3.real<<"+"<<c3.imag<<endl;
    return input;
}
int main()
{
    dlbcomplex c1,c2,c3;
    cout<<输入你要计算的两个复数<<endl;
    cin>>c1;
    cin>>c2;
    char a;
    cout<<给出你要的计算方式<<endl;
    cin>>a;
    if(a=="+")
    {c3=c1+c2;
    c3.display();
    }
    else
    {c3=c1-c2;
    c3.display();
    }
    return(0);
}