class Person {
public:
	Person(int age);
public:
	Person();
	int age;
};

Person::Person(int age) {
	this->age = age;
}


Person::Person() {
	this->age = 18;//默认18
}

ostream& operator<<(ostream& cout, Person p) {//
	cout << p.age;
	return cout;
}

//调用时this->operator++可简化为++*this,可以 ++(++*this)
Person& operator++(Person& p) {
	p.age = p.age + 1;
	return p;
}

//调用时this->operator++(int)可简化为*this++；不可以(*this++)++
 Person operator++(Person& p,int) {
	Person p1(p);
	p.age = p.age + 1;
	return p1;
}



void test() {
	int a = 12;
	Person person(18);
	cout << person << endl;
	cout << ++(++person) << endl;
	cout << person++ << endl;
	cout << person;

}

int main() {
	test();
}