C++核心编程 14（三）递增（减）运算符重载

C++核心编程 14（三）递增（减）运算符重载

目录

递增运算符重载  前置++的效率略高于后置++，原因是前置不会调用拷贝构造

递减运算符重载

---

++和--对于默认数据类型编译器都知道该如何递增递减，但是对于自定义数据类型，编译器不知道该如何运算，于是需要用到重载。

递增运算符重载

        1.前置++

class MyInter
{
public:
	MyInter()
	{
		this->m_Num = 0;
	}
	//重置前置++
	MyInter& operator++()
	{
		//先++
		m_Num++;
		//后返回
		return *this;
	}
private:
	int m_Num;
};

        2.后置++

class MyInter
{
public:
	friend ostream& operator<<(ostream& cout, MyInter& myInt);
	MyInter()
	{
		this->m_Num = 0;
	}
	//重置后置++
	MyInter operator++(int)
	{
		//先返回
		MyInter temp=*this;
		//后++
		this->m_Num++;
		return temp;
	}
private:
	int m_Num;
};

递减运算符重载

        1.前置--

class MyInter
{
public:
	MyInter()
	{
		this->m_Num = 0;
	}
	//重置前置--
	MyInter& operator--()
	{
		//先--
		m_Num--;
		//后返回
		return *this;
	}
private:
	int m_Num;
};

        2.后置--

class MyInter
{
public:
	MyInter()
	{
		this->m_Num = 0;
	}
	//重置后置--
	MyInter operator--(int)
	{
		//先返回
		MyInter temp=*this;
		//后--
		this->m_Num--;
		return temp;
	}
private:
	int m_Num;
};