C++运算符重载endl不能写？

Question

C++重载运算符“/”，使两个复数相除。
但去掉主函数中的endl才能正常运行，查了相关资料还是没明白，请问这是为什么呢？

#include <iostream>
using namespace std;
class Complex
{
    public:
        Complex(float x=0,float y=0){real=x;imag=y;}
        Complex operator/(Complex &c2);
        void display()
        {
            if (imag>0)
            cout<<real<<'+'<<imag<<'i'<<endl;
            else
            cout<<real<<imag<<'i'<<endl;
        }
    private:
        float real;
        float imag;        
};

Complex Complex::operator/(Complex &c2)

{
    Complex c;
    c.real=(real*c2.real-imag*c2.imag)/(c2.real*c2.real-c2.imag*c2.imag);
    c.imag=(real*c2.imag+c2.real*imag)/(c2.real*c2.real-c2.imag*c2.imag);
    return c;
}

int main()
{
    Complex complex1(1,2),complex2(3,4),complex;
    cout<<"complex1="; complex1.display();
    cout<<"complex2="; complex2.display();
    complex=complex1/complex2;
    cout<<"complex=";complex.display()<<endl;
    return 0;
}

Answer 1

endl是换行啊，跟着cout输出才可以，你写的那个是跟在函数后面，不符合语法要求