父类指针访问子类成员变量

1、父类指针获取子类成员变量

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Base {
 6 public:
 7     virtual void get() {}
 8 };
 9 
10 class Derive :public Base
11 {
12 public:
13     Derive(){}
14     void get() {
15         printf("The third element is %d\n", _x[2]);
16     };
17     int _x[6] = { 0,1,2,3,4,5 };
18 };
19 
20 int main()
21 {
22     Base *base = new Derive();
23     base->get();
24 
25     return 0;
26 }

2、类型转换

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Base
 6 {
 7 public:
 8     void virtual Func()
 9     {
10         cout << "Base\n";
11     }
12 };
13 
14 class Derived : public Base
15 {
16 public:
17     void Func()
18     {
19         cout << "Derived\n";
20     }
21 
22     void NewFunc()
23     {
24         cout << "New func\n";
25     }
26     int x[5] = { 0,1,2,3,4 };
27 };
28 
29 int main()
30 {
31     Base* b = new Derived();
32     b->Func();
33     
34     Derived* d =dynamic_cast<Derived*>(b) ;
35     // 不安全的转换
36     //Derived* d = (Derived*)b;
37     d->NewFunc();
38     cout << d->x[2] << endl;
39 
40     return 0;
41 }

 

posted on 2018-03-05 10:51  lina2014  阅读(2685)  评论(0)    收藏  举报

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