1.通过派生类的对象直接访问。前提是public继承
2.通过基类成员函数直接访问基类成员。无论哪种继承方式。基类的public和private都不可以以这种方式访问
3.通过基类名称访问被派生类重定义所隐藏的成员
1 #include<bits/stdc++.h>
2 using namespace std;
3
4 class Rectangle
5 {
6 public:
7 void setLength(double h) {
8 length = h;
9 }
10 void setWidth(double w)
11 {
12 width = w;
13 }
14 double getLength()
15 {
16 return length;
17 }
18 double getWidth()
19 {
20 return width;
21 }
22 double area()
23 {
24 return width*length;
25 }
26 double volume()
27 {
28 return 0;
29 }
30 void print()
31 {
32 cout << "\nLength = " << length << "\nWidth = " << width;
33 }
34 protected:
35 double length;
36 double width;
37 };
38
39 class Cube:public Rectangle
40 {
41 public:
42 void setHigh(double h)
43 {
44 high = h;
45 }
46 double getHigh()
47 {
48 return high;
49 }
50 double area()
51 {
52 //重定义area函数
53 return 2*(width*length + width*high + high*length);
54 }
55 double volume()
56 {
57 return width*length*high;
58 }
59
60 void print()
61 {
62 Rectangle::print();
63 cout << "\nhigh = " << high << endl;
64 }
65 private:
66 double high;
67 };
68
69 int main()
70 {
71 Cube c1;
72 c1.setLength(4);
73 c1.setHigh(3);
74 c1.setWidth(5);
75
76 c1.Rectangle::print();
77 c1.print();
78 cout << "Cube area = " << c1.area() << endl;
79 cout << "Cube bottom area = " << c1.Rectangle::area() << endl;
80 cout << "Cube volume = " << c1.volume() << endl;
81 return 0;
82 }