管理指针成员

#include <iostream>#include "plain-ptr.h"#include "value-ptr.h"#include "smart-ptr.h"using namespace std;void test_AHasPtr(){int i = 42;AHasPtr p1(&i, 42);AHasPtr p2 = p1;cout << p2.get_ptr_val() << endl;  // 输出是42p1.set_ptr_val(0);cout << p2.get_ptr_val() << endl;  // 输出是0int *ip = new int(42);AHasPtr ptr(ip, 10);cout << ptr.get_ptr_val() << endl;delete ip;cout << ptr.get_ptr_val() << endl;}void test_CHasPtr(){int obj = 0;CHasPtr ptr1(obj, 42);CHasPtr ptr2(ptr1);cout << ptr1.get_ptr_val() << ", " << ptr1.get_int() << endl;  // 0 和42cout << ptr2.get_ptr_val() << ", " << ptr2.get_int() << endl;   // 0 和42ptr2.set_ptr_val(6);ptr2.set_int(66);cout << "修改后的：" << endl;cout << ptr1.get_ptr_val() << ", " << ptr1.get_int() << endl;  // 0 和42cout << ptr2.get_ptr_val() << ", " << ptr2.get_int() << endl;   // 6 和66}void test_BHasPtr(){int obj = 0;BHasPtr ptr1(&obj, 42);BHasPtr ptr2(ptr1);cout << ptr1.get_ptr_val() << ", " << ptr1.get_int() << endl;  // 0 和42cout << ptr2.get_ptr_val() << ", " << ptr2.get_int() << endl;   // 0 和42cout << "修改后的：" << endl;ptr2.set_ptr_val(6);ptr2.set_int(66);cout << ptr1.get_ptr_val() << ", " << ptr1.get_int() << endl;  // 6 和42cout << ptr2.get_ptr_val() << ", " << ptr2.get_int() << endl;   // 6 和66}int main(){cout << "常规指针：" << endl;test_AHasPtr();cout << endl << "值型类：" << endl;test_CHasPtr();cout << endl << "智能指针类：" << endl;test_BHasPtr();return 0;}

class AHasPtr{public:AHasPtr(int *p, int i) :ptr(p),val(i){}int *get_ptr() const { return ptr; }int get_int() const { return val; }void set_ptr(int *p) { ptr = p; }void set_int(int i) { val = i; }int get_ptr_val() const { return *ptr; }void set_ptr_val(int val) const { *ptr = val; }private:int val;int *ptr;   // 指针复制就是浅复制，复制的是指针的地址，};

class U_Ptr{friend class BHasPtr; // 友元类，private:int *ip;size_t use; // 计数，U_Ptr(int *p) :ip(p), use(1) {}~U_Ptr() { delete ip; }};class BHasPtr{public:BHasPtr(int *p, int i) :ptr(new U_Ptr(p)), val(i){}BHasPtr(const BHasPtr &orig) :ptr(orig.ptr), val(orig.val)  // 复制构造函数，{++ptr->use; // 讲计数器加一，}BHasPtr& operator=(const BHasPtr&);   //赋值操作符，~BHasPtr()  // 析构函数，将其计数减减，{if (--ptr->use == 0) delete ptr;}int *get_ptr() const { return ptr->ip; }  // ptr->ip 这个代表的是智能指针里有一个普通指针int get_int() const { return val; }void set_ptr(int *p) { ptr->ip = p; }void set_int(int i) { val = i; }int get_ptr_val() const { return *ptr->ip; }void set_ptr_val(int val) const { *ptr->ip = val; }private:int val;//int *ptr;   // 指针复制就是浅复制，复制的是指针的地址，U_Ptr *ptr; // 这个是智能指针，U_ptr是一个智能指针类，};BHasPtr& BHasPtr::operator = (const BHasPtr& rhs){++rhs.ptr->use; // 右边的++if (--ptr->use == 0) delete ptr;  // 左边的——ptr = rhs.ptr;val = rhs.val;return *this;}

class CHasPtr{public:CHasPtr(const int &p, int i) :ptr(new int (p)), val(i){}CHasPtr(const CHasPtr &orig):ptr(new int(*orig.ptr)), val(orig.val) {}      // 这个是复制构造函数，CHasPtr& operator = (const CHasPtr&);  // 赋值操作符，~CHasPtr() { delete ptr; }  // 析构函数，int *get_ptr() const { return ptr; }int get_int() const { return val; }void set_ptr(int *p) { ptr = p; }void set_int(int i) { val = i; }int get_ptr_val() const { return *ptr; }void set_ptr_val(int val) const { *ptr = val; }private:int val;int *ptr;   // 指针复制就是浅复制，复制的是指针的地址，};CHasPtr& CHasPtr::operator = (const CHasPtr &rhs){*ptr = *rhs.ptr;val = rhs.val;return *this;}