运算符重载（作为普通函数）

 1 #include<iostream>
 2 using namespace std;
 3 class Complex{
 4 public:
 5     double real;
 6     double imaginary;
 7     Complex(double a=0.0,double b=0.0) : real(a),imaginary(b) {}//初始化 
 8     ~Complex(){}
 9     void print(); 
10 };
11 Complex operator+(Complex& a,Complex& b)//运算符重载函数(作为普通函数) 
12     {
13         return Complex(a.real+b.real,a.imaginary+b.imaginary);
14     }
15 void Complex::print()
16 {
17     cout<<real<<"+"<<imaginary<<"i"<<endl; 
18 }
19 int main()
20 {
21     Complex a(3,2),b(5,4),c;
22     c=a+b;
23     c.print();
24     return 0;
25 }