void fun(const int *pvar); void fun(const int &rval); 分析:上述写法传递的为地址,因此函数内很可能改变参数指向的变量,使用const可有效限定参数在函数体中不可被改变。 结论:除的确需要在函数内改变指针参数指向的变量,一般以地址传递的参数加上const是不错的风格. (2).const 限定函数的值型返回值: cons...
void fun1() const{} int fun2() const { return a; } private: int a; } class one_virtual { public: virtual void fun1() const{} int fun2() const { return a; } private: int a; } class two_virtual { public: virtual void fun1() const{} virtual int fun2() const { return a...
void setID(Simple* const this, int id){this->m_id = id;} *this储存了当成员函数被调用的时候、对象的地址。通过“ this-> ”能够实现。当this指向s1的地址的时候,那么“this->m_id”能够演化为s1.m_id。 总结: 当我们调用s1.setID(2)的时候,编译器实际上调用的是setID(&s1,2)。 在setID...
每一个派生类定义了自己的构造函数,并且使用合适的定义将各自继承而来的虚函数覆写了。 Listing 5 A function that returns the shape with the largest area in a collection of shapes const shape *largest(const shape *sa[], size_t n) { const shape *s = 0; double m = 0; double a; for (si...
### 虚函数(Virtual Function) 虚函数是指在基类中使用`virtual`关键字声明的函数。它的目的是允许派生类重写该函数,从而在运行时通过基类指针或引用调用派生类的实现。 ```cpp class Base { public: virtual void display() const { std::cout << "Base display" << std::endl; } }; class Derived :...
virtual means exactly and only "this is a new virtual function." virual明确表示而且只用于表示"这是一个新的虚函数" override means exactly and only "this is a non-final overrider." overide明确表示而且只表示“这不是最终覆盖者” final means exactly and only "this is a final overrider." ...
virtual means exactly and only "this is a new virtual function." virual明确表示而且只用于表示"这是一个新的虚函数" override means exactly and only "this is a non-final overrider." overide明确表示而且只表示“这不是最终覆盖者” final means exactly and only "this is a final overrider." ...
The functionB::freturns a reference or pointer to a class of typeT, andA::freturns a pointer or a reference to an unambiguous direct or indirect base class ofT. The const or volatile qualification of the pointer or reference returned byB::fhas the same or less const or volatile qualifica...
classShape{public:virtual~Shape()=default;virtual doublearea()const=0;};classCircle:publicShapeclassRectangle:publicShape// virtualstaticvoidBM_VirtualFunction(benchmark::State&state){std::vector<std::unique_ptr<Shape>>shapes;shapes.reserve(1000);for(int i=0;i<1000;++i){if(i%2==0){shapes...