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

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