[C++]operator运算符重载 +, -, []

1. +，- 运算符重载

#include 

class Complex{
public:
    Complex(int x, int y):a(x), b(y){};
    ~Complex(){};
    Complex operator - (const Complex &c);
    int a;
    int b;
};

Complex operator + (const Complex &x,  const Complex &y){
    return Complex(x.a + y.a, x.b + y.b);
}

Complex Complex::operator - (const Complex &c){
    a = a - c.a;
    b = b - c.b;
    return *this;
}

int main(){
    Complex test_a(8,9);
    Complex text_b(5,5);
    test_a = test_a - text_b;
    std::cout << test_a.a < 
运行结果：
 3
 4
 
[] 运算符重载
 
#include 

class my_vertor{
public:
    my_vertor(){};
    ~my_vertor(){};
    int str[8] = {1,2,3,4,5,6,7,8};
    int operator [] (int x);
    int num;
};

int my_vertor::operator [](int x){
    return str[x];
}


int main(){
    my_vertor m_ver;
    std::cout<< m_ver[2] < 
运行结果：
 3