C + + Learning notes-smart pointers

Smart pointers are designed to facilitate the management of dynamic memory and to automatically manage the objects pointed to by the release.

There are three kinds of smart pointers: 1, shared_ptr allows multiple pointers to the same object, 2, unique_ptr the object that the exclusive points to, and 3, weak_ptr is a companion class, which is a weak reference to the object that shared_ptr manages. These three types are defined in the memory header file.

Here is a code for implementing the smart pointers that you see on the Web:

Class U_ptr {friend class hasptr;int *ip;size_t use; u_ptr (int *p): IP (P), use (1) {cout << "U_ptr constructor called!" << Endl;} ~u_ptr () {delete Ip;cout << "u_ptr distructor called!" << Endl;}}; Class Hasptr {public:hasptr (int *p, int i):p tr (new U_ptr (P)), Val (i) {cout << "Hasptr constructor called!" &LT;&L T "Use =" << ptr->use << Endl;} Hasptr (const hasptr& orig):p tr (orig.ptr), Val (orig.val) {++ptr->use;cout << "Hasptr copy constructor Called! "<<" use = "<< ptr->use<< Endl;}  hasptr& operator= (const hasptr&); ~hasptr () {cout << "hasptr distructor called!" << "use =" << Ptr->use << endl;if (--ptr->use = = 0) delete ptr;} int *get_ptr () const {return ptr->ip;} int Get_int () const {return val;} void set_ptr (int *p) const {PTR-&GT;IP = P;} void Set_int (int i) {val = i;} int Get_ptr_val () const {return *ptr->ip;} void Set_ptr_val (int i) {*ptr->ip = i;} Private:u_ptr *ptr;int Val;}; hasptr& Hasptr::operator = (const hasptr &AMP;RHS) {//note, here the assignment operator adds 1 to the use of RHS before reducing the use count of the operands, thus preventing self-assignment ++rhs.ptr-> Use;if (--ptr->use = = 0) Delete ptr;ptr = Rhs.ptr;val = Rhs.val;return *this;}

C + + Learning notes-smart pointers