新标准C++程序设计读书笔记_继承和多态

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 
 5 class CStudent 
 6 {
 7 private:
 8     string name;
 9     string id; //学号
10     char gender; //性别,‘F‘代表女， ‘M‘代表男
11     int age;
12 public:
13     void PrintInfo();
14     void SetInfo( const string & name_,const string & id_,
15     int age_, char gender_ );
16     string GetName() { return name; }
17 };
18 
19 void CStudent::PrintInfo()
20 {
21     cout << "Name:" << name << endl;
22     cout << "ID:" << id << endl;
23     cout << "Age:" << age << endl;
24     cout << "Gender:" << gender << endl;
25 }
26 
27 void CStudent::SetInfo( const string & name_,const string & id_,
28 int age_,char gender_ )
29 {
30     name = name_;
31     id = id_;
32     age = age_;
33     gender = gender_;
34 }
35 
36 class CUndergraduateStudent : public CStudent
37 {
38 //本科生类，继承了CStudent类
39 private:
40     string department; //学生所属的系的名称
41 public:
42     void QualifiedForBaoyan() 
43     { 
44         //给予保研资格
45         cout << “qualified for baoyan” << endl;
46     }
47 
48     void PrintInfo() 
49     {
50         CStudent::PrintInfo(); //调用基类的PrintInfo
51         cout << “Department:” << department <<endl;
52     }
53 
54     void SetInfo( const string & name_,const string & id_,
55     int age_,char gender_ ,const string & department_) 
56     {
57         CStudent::SetInfo(name_,id_,age_,gender_); //调用基类的SetInfo
58         department = department_;
59     }
60 };
61 
62 int main()
63 {
64     CUndergraduateStudent s2;
65     s2.SetInfo(“Harry Potter ”, “118829212”,19,‘M’,“Computer Science”);
66     cout << s2.GetName() << “ ” ;
67     s2.QualifiedForBaoyan ();
68     s2.PrintInfo ();
69     return 0;
70 }

1 class CPoint
2 {
3     double x,y;
4 };
5 
6 class CCircle : public CPoint
7 {
8     double r;
9 };

 1 class CPoint
 2 {
 3     double x,y;
 4     //便于Ccirle类操作其圆心
 5     friend class CCircle;
 6 };
 7 
 8 class CCircle
 9 {
10     double r;
11     CPoint center;
12 };

 1 class Father 
 2 {
 3 private: 
 4     int nPrivate; //私有成员
 5 public: 
 6     int nPublic; //公有成员
 7 protected: 
 8     int nProtected; // 保护成员
 9 };
10 
11 class Son : public Father
12 {
13     void AccessFather () 
14     {
15         nPublic = 1; // ok;
16         nPrivate = 1; // wrong
17         nProtected = 1; // OK，访问从基类继承的protected成员
18         Son f;
19         f.nProtected = 1; //wrong ，f不是当前对象
20     }
21 };
22 
23 int main()
24 {
25     Father f;
26     Son s;
27     f.nPublic = 1; // Ok
28     s.nPublic = 1; // Ok
29     f.nProtected = 1; // error
30     f.nPrivate = 1; // error
31     s.nProtected = 1; //error
32     s.nPrivate = 1; // error
33     return 0;
34 }