C++ 递增/递减运算符重载

作用： 通过重载递增运算符，实现自己的整型数据

总结： 前置递增返回引用，后置递增返回值

递增

#include
using namespace std;

class MyInteger {
private:
	int m_Num = 0;
public:
	friend ostream& operator<<(ostream& out, MyInteger myint);
	MyInteger() {
		m_Num = 0;
	}
	//重载前置++运算符  返回引用是一直对一个数据进行递增
	MyInteger& operator++() {
		//先++
		m_Num++;
		//再返回
		return *this;
	}
	//重载后置置++运算符
	MyInteger& operator++(int) {  //int代表占位参数，可以用于区分前置和后置递增
		//先返回
		MyInteger temp = *this; 
		//记录当前本身的值，然后让本身的值+1，但是返回的是以前的值，达到先返回后++
		//再++
		m_Num++;
		return temp;
	}
};

//重载左运算符
ostream& operator<<(ostream& out, MyInteger myint) {
	out << myint.m_Num;
	return out;
}

void test01() {
	MyInteger myInt;
	cout << ++myInt << endl;
	cout << myInt << endl;
}

void test02() {
	MyInteger myInt;
	cout << myInt++ << endl;
	cout << myInt << endl;
}


int main()
{
	test01();
	test02();
	return 0;
}

递减

#include
using namespace std;

class MyInteger {
private:
	int m_num;
public:
	MyInteger() {
		m_num = 0;
	}
	//！！！！！！！ 必须用引用
	MyInteger &operator--() {
		//先++后运算
		m_num--;
		return *this;
	}
	//！！！！！！！ 必须用引用
	MyInteger &operator--(int) {
		//先传值后++
		MyInteger temp = *this;
		m_num--;
		return temp;
	}
	friend ostream& operator<<(ostream& out, MyInteger myint);
};

//重载左运算符
ostream& operator<<(ostream& out, MyInteger myint) {
	out << myint.m_num;
	return out;
}

void test01() {
	MyInteger myInt;
	cout << --(--myInt) << endl;
	cout << myInt << endl;
}

void test02() {
	MyInteger myInt;
	cout << myInt-- << endl;
	cout << myInt << endl;
}


int main()
{
	test01();
	test02();
	return 0;
}