风之客-例题2.ppt

1、例题2,定义类Point，有坐标数据成员x和y，取X坐标函数GetX(void);取Y坐标函数GetY(void); 构造函数Point(float xx, float yy); 和析构函数Point(); 定义类Distance, 有对象数据成员p1, p2和距离数据dist；构造函数Distance (Point a,Point b); 计算两点距离函数GetDis(void) 定义两个Point类对象myp1(1,1), myp2(4,5); 定义一个Distance类对象myd(p1, p2); 主程序实现求两点间的距离,例题2-1,class Point private: float

2、 x,y; /点的坐标 public: Point(float xx, float yy); /构造函数 Point(); float GetX(void); /取X坐标 float GetY(void); /取Y坐标 ,Point:Point(float xx,float yy) X=xx; Y=yy; Point:Point（ ） float Point:GetX(void) return x; folat Point:GetY(void) return y;,class Distance private: Point p1, p2; /线段的两个端点 double dist; publi

3、c: Distance (Point a,Point b); /构造函数 double GetDis(void) return dist; /计算距离 ;,Distance: Distance (Point a, Point b): p1(a), p2(b) double x=double(p1.GetX()-p2.GetX(); double y=double(p1.GetY()-p2.GetY(); dist=sqrt (x*x-y*y) ;,void main() Point myp1(1,1), myp2(4,5); Distance myd(p1, p2); cout“the dis

4、tance is: ”endl; coutmyd.GetDis()endl; ;,例题2-2,class Point private: float x,y; /点的坐标 public: Point(float xx, float yy); /构造函数 Point(); float GetX(void); /取X坐标 float GetY(void); /取Y坐标 ,Point:Point(float xx,float yy) X=xx; Y=yy; Point:Point（ ） float Point:GetX(void) return x; folat Point:GetY(void) re

5、turn y;,class Distance private: Point p1, p2; /线段的两个端点 double dist, price; public: Distance (Point a,Point b); /构造函数 double GetDis(void) return dist; /计算距离 ;,Distance: Distance (Point a, Point b, double p=3): p1(a), p2(b) double x=double(p1.GetX()-p2.GetX(); double y=double(p1.GetY()-p2.GetY(); dist

6、=sqrt (x*x-y*y) price=p ;,Distance: Distance (Point a, Point b, double p=3): p1(a), p2(b) double x=double(p1. x-p2.x); /? double y=double(p1.y-p2.y); /? dist=sqrt (x*x-y*y) price=p ;,例题2-3具有静态数据成员的Point,class Point private: float x,y; /点的坐标 static int countP; public: Point(float xx, float yy); /构造函数

7、 Point(Point ,Point:Point(float xx,float yy) X=xx; Y=yy; countP+; Point:Point(Point ,void main() Point A(4,5); cout“Point A: ”A.GetX()“,”A.GetY()endl; Point B(A); cout“Point B: ”B.GetX()“,”B.GetY()endl; B.GetC(); ;,例题2-4具有静态成员函数的Point,class Point private: float x,y; /点的坐标 static int countP; public:

8、Point(float xx, float yy); /构造函数 Point(Point ,Point:Point(float xx,float yy) X=xx; Y=yy; countP+; Point:Point(Point ,void main() Point A(4,5); cout“Point A: ”A.GetX()“,”A.GetY()endl; A.GetC(); Point B(A); cout“Point B: ”B.GetX()“,”B.GetY()endl; Point:GetC(); ;,例题2-5具有静态成员函数的类,class A private: int x;

9、 public: static void f(A a); Void A:f(A a) coutxendl; /? couta.xendl; ,例题2-6具有静态成员函数的类,class Application private: static int global; public: static void f(); static void g(); int Application:global=0;,void Application:f() global=5; void Application:g() coutglobalendl; int main() Application:f(); App

10、lication:g(); return 0; ,阅读程序1具有静态数据成员和函数的类,class Student public: Student( int StudentNo=0) cout“creat one student”endl; NoOfStudent+; cout“NoOfStudent” NoOfStudent; StudentNo=200502100+ NoOfStudent; cout“StudentNo”StudentNoendl; Student() cout“delete one student”endl; NoOfStudent-; ,static int numb

11、er() return NoOfStudent; Protected: static int NoOfStudent; int StudentNo; int Student: NoOfStudent=0;,Void fn() Student S1; Student S2; coutStudent:number()endl; void main() fn(); coutStudent:number()endl; ,例题3-1,class C private: int x; public: C (int a) x=a; int GetX() return x; long Cube(C ,例题3-2

12、具有友元函数的类,class C private: int x; public: C (int a) x=a; int GetX() return x; friend long Cube(C ,void main() C c(5); coutCube(c)endl; ,例题3-2具有友元类的类,class A public: void Display() coutxendl; friend class B; private: int x; ,class B public: void Set (int i); void Display(); private: A a; void B:Set (int i) a.x=i; void B: Display() a.Display(); couta.xendl;,例题3-3使用友元函数计算两点距离,include # include class Point public: Point (int xx=0,yy=0) x=xx,y=yy; int GetX(); int GetY(); friend float fdist(Point ,Double fdist(Point ,例题3-4一个类的成员函数可以成为另外一个类的友元函数,class Student; clas