<< 链式重载

 #include <iostream>

 using namespace std;

 class Complex
 {
 private:
     int a, b;
 public:
     Complex(int a, int b) :a(a), b(b)
     {}
     friend ostream& operator<<(ostream &out, Complex &c);

     void operator+(Complex &c)          //放在类里
     {
           this->a = this->a + c.a;
           this->b = this->b + c.b;
           //return *this;
     }

 };

 ostream& operator<<(ostream &out, Complex &c)
 {
     out << "a = " << c.a << "  b = " << c.b;
     return out;
 }

 int main()
 {
     Complex c1(, ), c2(, );

     cout << c1 << "showmethemoney" << "aaaaa" << c1 << endl;
     //输出c1之后,返回cout(重载函数中手工返回),接着输出两个字符串(系统本身功能),再次返回cout(系统函数所定义的返回),最后又输出c1(重载函数功能),返回cout,最后endl;
     system("pause");
     return ;
 }