重载赋值操作符和副本构造器的问题，去掉 const 关键词就正常了，为啥？

liudanai2844

1. # include <iostream>
   
2. # include <string>
   
3. 
   
4. using namespace std;
   
5. 
   
6. struct Keyboard
   
7. {
   
8.         string m_clavier;
   
9.         string m_mouse;
   
10. };
    
11. 
    
12. class Comstru
    
13. {
    
14. public:
    
15.         Comstru();
    
16.         Comstru(const Comstru& com);
    
17. 
    
18.         Comstru& operator =(const Comstru& com);
    
19.         Keyboard* getKeyboard();
    
20. 
    
21. protected:
    
22.         Keyboard* m_pKeyboard;
    
23.         string m_strmodel;
    
24. };
    
25. 
    
26. Comstru::Comstru()
    
27. {
    
28.         m_pKeyboard = new Keyboard;
    
29. }
    
30. 
    
31. Comstru::Comstru(const Comstru& com)
    
32. {
    
33.         *this = com;
    
34. }
    
35. 
    
36. Keyboard* Comstru::getKeyboard()
    
37. {
    
38.         return m_pKeyboard;
    
39. }
    
40. 
    
41. Comstru& Comstru::operator =(const Comstru& com)
    
42. {
    
43.         if (this != &com)
    
44.         {
    
45.                 m_strmodel = com.m_strmodel;
    
46.                 m_pKeyboard = new Keyboard( *(com.getKeyboard()) );
    
47.         }
    
48.        
    
49.         return *this;
    
50. }
    
51. 
    
52. int main()
    
53. {
    
54.         Comstru p1;
    
55. 
    
56.         (*(p1.getKeyboard())).m_clavier = "键盘";
    
57.         (*(p1.getKeyboard())).m_mouse = "鼠标";
    
58.        
    
59.         Comstru p2(p1);
    
60.         (*(p2.getKeyboard())).m_mouse = "鼠标222";
    
61.         cout << (*(p1.getKeyboard())).m_clavier << endl;
    
62.         cout << (*(p1.getKeyboard())).m_mouse << endl;
    
63. 
    
64.         return 0;
    
65. }

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去掉const 关键词就正常了，为啥？

liudanai2844

我顶{:1_1:}

liudanai2844

找到原因了，const调用了非const函数，第46行那里调用了非const的getKeyboard()函数，改成m_pKeyboard 属性就可以了。