c++之说_9_6|自定义类型 struct operator 重载运算符关键字

c++中 struct 和 class 特性几乎一模一样

所以很多都是共有的特性篇幅就很多了

c++中我觉得最牛皮的概念之一就是

重载运算符 operator 关键字

这个东西能将我们的运算符（+-*/） new delete

类型转换

写在类里面当成员函数并制定该类型变量运算时所适用的逻辑

以下是可重载的所有运算符：

这是重载运算符时的方式注意运算符替换掉 @

运算符前缀后缀放置位

限制或不可重载的符号


struct obj_3
{

	obj_3() {};
	obj_3(const int& Ina, const int& Inb) : a(Ina), b(Inb) {}


	int	geta()const { return a; };

	int	getb()const { return b; };


private:

	int a = 0;
	int b = 0;

};


struct obj_1
{

public:
	obj_1() { Ts = this;  };
	//使用了委托构造
	obj_1(const int& Ina, const int& Inb) : obj_1() { a = Ina; b = Inb; }


	int	geta() const { return a; };

	int	getb() const { return b; };
public:

	bool operator== (const obj_1& Target)
	{
		
		return  (this->a == Target.a) && (this->b == Target.b);
	};

	bool operator!= (const obj_1& Target)
	{

		return  !operator==(Target);
	};
	operator obj_3()
	{
		std::cout << __func__ << ":" << endl;
		return obj_3(99, 99);
	}

	void* operator new(std::size_t size, void* p, int io,char* c)
	{
		std::cout << "obj_1::" << __func__ << "(std::size_t size, void* p,char* c) :" << endl;
		std::cout << "operator new 构造的地址是：" << p << endl;
		std::cout << "operator new   io ：" << io << endl;
		std::cout << "operator new   c ：" << c << endl;
		return p;
	}

	void operator delete(void* p,size_t size, const char* c)
	{
		std::cout << "obj_1::" << __func__ << "(void* p,size_t size, const char* c) :" << endl;
		std::cout << "operator delete的地址是：" << p << endl;
		std::cout << "operator delete   size ：" << size << endl;
		std::cout << "operator delete   c ：" << c << endl;
		return;

	}


	int	operator[](int i)
	{
		std::cout << "obj_1::" << __func__ << "(int i) :" << endl;
		std::cout << "i = "<< i << endl;
		return a + i;
	}

	~obj_1() {};


private:

	obj_1* Ts;

	int a = 0;
	int b = 0;

};

struct obj_2
{

	obj_2() {};
	obj_2(const int& Ina, const int& Inb) : a(Ina), b(Inb) {}


	int	geta()const { return a; };

	int	getb()const { return b; };

	obj_2& operator= (const obj_1& Target)
	{

		std::cout << "obj_2::" << __func__ << "(const obj_1& Target) :" << endl;

		this->a = Target.geta();
		this->b = Target.getb();

		return *this;
	};

	operator obj_1()
	{

		std::cout << "obj_2::" << __func__ << ":" << endl;
		return	obj_1(this->a, 100);
	}


	~obj_2() {};


private:

	int a = 0;
	int b = 0;

};


int main()
{
	std::cout << __func__ <<":"<< endl;

	obj_1 a1(10, 1000);
	obj_2 b2(50, 10);
	obj_3 c3;
	obj_1 texta1;
	obj_2 textb2;


	std::cout << "初始化完各个对象的值" << endl;
	std::cout << "a1.a: "<<a1.geta() << endl;
	std::cout << "a1.b: " << a1.getb() << endl;
	std::cout << "b2.a: " << b2.geta() << endl;
	std::cout << "b2.b: " << b2.getb() << endl;
	std::cout << "c3.a: " << c3.geta() << endl;
	std::cout << "c3.b: " << c3.getb() << endl;
	std::cout << "texta1.a: " << texta1.geta() << endl;
	std::cout << "texta1.b: " << texta1.getb() << endl;
	std::cout << "textb2.a: " << textb2.geta() << endl;
	std::cout << "textb2.b: " << textb2.getb() << endl;

	textb2 =	a1;
	std::cout << "该操作完成时各个变量的值" << endl;
	std::cout << "a1.a: " << a1.geta() << endl;
	std::cout << "a1.b: " << a1.getb() << endl;
	
	std::cout << "textb2.a: " << textb2.geta() << endl;
	std::cout << "textb2.b: " << textb2.getb() << endl;
	
	texta1 = (obj_1)b2;
	std::cout << "该操作完成时各个变量的值" << endl;
	
	std::cout << "b2.a: " << b2.geta() << endl;
	std::cout << "b2.b: " << b2.getb() << endl;
	
	std::cout << "texta1.a: " << texta1.geta() << endl;
	std::cout << "texta1.b: " << texta1.getb() << endl;
	
	c3 = a1;
	std::cout << "该操作完成时各个变量的值" << endl;
	std::cout << "a1.a: " << a1.geta() << endl;
	std::cout << "a1.b: " << a1.getb() << endl;
	
	std::cout << "c3.a: " << c3.geta() << endl;
	std::cout << "c3.b: " << c3.getb() << endl;


	std::cout << "a1[100]: " << a1[100] << endl;


	static char b[10] = { 0 };
	char p = '2';

	obj_1* pobj1 = ::new obj_1;

	obj_1* pobjw = new(b, 9000,&p) obj_1;
	
	::delete pobj1;
	obj_1::operator delete( pobjw,60,&p);



	return  0;
}

部分测试代码我已放上

接下来我们运行看看