引用计数

 1 #include <iostream>
 2 class CBuff
 3 {
 4 public:
 5     CBuff(const char* szBuff)
 6     {
 7         Init();
 8         SetBuff(szBuff);
 9     }
10     void SetBuff(const char* szBuff)
11     {
12         ReduceCount();
13 
14         m_pBuff = new char[strlen(szBuff) + 1];
15         m_pnCount = new int(1);
16         strcpy(m_pBuff, szBuff);
17     }
18     CBuff(const CBuff& buff)
19     {
20         m_pBuff = buff.m_pBuff;
21         m_pnCount = buff.m_pnCount;
22         (*m_pnCount)++;
23     }
24     ~CBuff()
25     {
26         ReduceCount();
27     }
28 private:
29     void ReduceCount()
30     {
31         if (m_pBuff==nullptr)
32         {
33             return;
34         }
35         (*m_pnCount)--;
36         if (*m_pnCount==0)
37         {
38             delete[]m_pnCount;
39             delete[]m_pBuff;
40             m_pBuff = nullptr;
41             m_pnCount = nullptr;
42         }
43     }
44     void Init()
45     {
46          m_pBuff=nullptr;
47          m_pnCount = nullptr;
48     }
49     char* m_pBuff;
50     int* m_pnCount;
51 };
52 
53 
54 int main()
55 {
56 
57     CBuff buff1("hello");
58     CBuff buff2 = buff1;
59     CBuff buff3 = buff2;
60     buff1.SetBuff("pp");
61 
62     return 0;
63 }