海门做网站,flask网站开发视频,常见的网站开发环境,新安江大桥最新消息C多态 1.1多态性(polymorphism)是面向对象程序设计的一个重要特征。1.2从系统实现的角度看#xff0c;多态性分两类#xff1a;静态多态性与动态多态性。静态多态性是通过函数重载(运算符重载也是函数重载)来实现的。它又称为编译时多态。动态多样性是在程序运行过程中才动态…C多态
1.1多态性(polymorphism)是面向对象程序设计的一个重要特征。1.2从系统实现的角度看多态性分两类静态多态性与动态多态性。静态多态性是通过函数重载(运算符重载也是函数重载)来实现的。它又称为编译时多态。动态多样性是在程序运行过程中才动态确定操作所针对的对象。它又称为运行时多态动态多态性是通过虚函数来实现的。1.3一段代码#include iostream using namespace std; class Point { public: Point(float a0,float b0); void setPoint(float a,float b); float getX() const {return x;} float getY() const {return y;} friend ostream operator (ostream output,Point p); protected: float x,y; }; Point::Point(float a, float b) { xa; yb; } void Point::setPoint(float a, float b) { xa; yb; } ostream operator (ostream output,Point p) { output [ p.getX() , p.getY() ] endl; return output; } class Circle:public Point { public: Circle(float a,float b,float r):Point(a,b),radius(r){} void setRadius(float r); float getRadius() const {return radius;} float area() const; friend ostream operator (ostream output,Circle c); protected: float radius; }; void Circle::setRadius(float r) { radiusr; } float Circle::area() const { return 3.14159*radius*radius; } ostream operator (ostream output,Circle c) { output Center [ c.x , c.y ] radius c.radius area c.area() endl; return output; } class Cylinder:public Circle { public: Cylinder(float a,float b,float r,float h):Circle(a,b,r),height(h){} void setHeight(float h){heighth;} float getHeight() const{return height;} float area() const; float volume() const; friend ostream operator (ostream output,Cylinder cy); protected: float height; }; float Cylinder::area() const { return 2*Circle::area()2*3.14159*radius*height; } float Cylinder::volume() const { return Circle::area()*height; } ostream operator (ostream output,Cylinder cy) { output Center [ cy.getX() , cy.getY() ] r cy.radius \narea cy.area() volume cy.volume() endl; return output; } int main() { Cylinder cy(1,2,3,4); cout Cylinder\n Center [ cy.getX() , cy.getY() ] r cy.getRadius() \narea cy.area() volume cy.volume() endl; cy.setHeight(1); cy.setPoint(2,3); cy.setRadius(4); cout Cylinder\n cy endl; Point pcy; cout Point\n p; Circle ccy; cout Circle\n c; return 0; } 1.4在本例中存在静态多态性这是由运算符重载引起的可以看到在编译时编译系统即可以判定应调用哪个运算符函数。
