c++ 加号运算符重载

以下是两种C++中加号运算符重载的例子：

1. 类内重载

class Person {
public:
    Person operator+(const Person& p) {
        Person tmp;
        tmp.age = this->age + p.age;
        return tmp;
    }
    int age;
};

void test01() {
    Person p1;
    p1.age = 20;
    Person p2(p1);
    Person p3 = p1 + p2; // 或者写为 p3 = p1.operator+(p2)
    cout << p3.age << endl;
}

int main() {
    test01();
    return 0;
}

2. 类外重载

class Person {
public:
    int age;
};

Person operator+(const Person& p1, const Person& p2) {
    Person tmp;
    tmp.age = p1.age + p2.age;
    return tmp;
}

void test01() {
    Person p1;
    p1.age = 20;
    Person p2(p1);    Person p3 = p1 + p2; // 或者写为 Person p3 = operator+(p1, p2);
    cout << p3.age << endl;
}

int main() {
    test01();
    return 0;
}