学步园

#include "stdafx.h"</p> <p>#include <iostream><br /> using namespace std; </p> <p>class HasPtr;<br /> class U_Ptr<br /> {<br /> friend class HasPtr;<br /> int *ip;<br /> size_t use;</p> <p> U_Ptr(int *p): ip(p), use(1) { }</p> <p> ~U_Ptr()<br /> {<br /> delete ip;<br /> }<br /> };</p> <p>class HasPtr<br /> {<br /> public:<br /> HasPtr(int *p,int i): ptr(new U_Ptr(p)),val(i) { }</p> <p> HasPtr(const HasPtr &orig)<br /> {<br /> ptr=orig.ptr;<br /> val=orig.val;</p> <p> ++ptr->use;<br /> }</p> <p> HasPtr &operator = (const HasPtr &);</p> <p> int *get_ptr() const<br /> {<br /> return ptr->ip;<br /> }</p> <p> int get_int() const<br /> {<br /> return val;<br /> }</p> <p> void set_ptr(int *p)<br /> {<br /> ptr->ip = p;<br /> }</p> <p> void set_int(int i)<br /> {<br /> val = i;<br /> }</p> <p> int get_ptr_val() const<br /> {<br /> return *ptr->ip;<br /> }</p> <p> void set_ptr_val(int i)<br /> {<br /> *ptr->ip = i;<br /> }</p> <p> ~HasPtr()<br /> {<br /> cout<<"load detructor!"<<endl;<br /> if (ptr->use==0)//注意这儿并需要--<br /> {<br /> delete ptr;<br /> }<br /> }<br /> private:<br /> U_Ptr *ptr;<br /> int val;<br /> };</p> <p>HasPtr& HasPtr::operator = (const HasPtr &rhs)<br /> {<br /> ++rhs.ptr->use;<br /> if (rhs.ptr->use==0)//注意这儿并需要--<br /> {<br /> delete ptr;<br /> }</p> <p> ptr=rhs.ptr;<br /> val=rhs.val;</p> <p> return *this;<br /> }<br /> int main()<br /> {<br /> int obj = 0;<br /> HasPtr ptr1(&obj, 42);<br /> HasPtr ptr2(ptr1);<br /> HasPtr ptr3(ptr2); </p> <p> return 0;<br /> }