C++学习基础七——深复制与浅复制

  1 #include <iostream>
  2 
  3 using namespace std;
  4 
  5 class ADemo
  6 {
  7 public:
  8     ADemo(int v, const int &p)
  9     {
 10         val = v;
 11         ptr = new int(p);
 12     }
 13     ~ADemo()
 14     {
 15         delete ptr;
 16     }
 17     
 18     ADemo(const ADemo &other)
 19     {
 20         val = other.val;
 21         ptr = new int;
 22         *ptr = *other.ptr;//深复制 
 23     }
 24     
 25     ADemo& operator=(const ADemo &other)
 26     {
 27         val = other.val;
 28         ptr = new int;
 29         *ptr = *other.ptr;//深复制 
 30         return *this;
 31     }
 32     
 33     int get_ptr_val()
 34     {
 35         return *ptr;
 36     }
 37     void set_ptr(int v)
 38     {
 39         *ptr = v;
 40     }
 41 private:
 42     int val;
 43     int *ptr;    
 44 };
 45 
 46 class BDemo
 47 {
 48     public:
 49     BDemo(int v, const int &p)
 50     {
 51         val = v;
 52         ptr = new int(p);
 53     }
 54     ~BDemo()
 55     {
 56         delete ptr;
 57     }
 58     
 59     BDemo(const BDemo &other)
 60     {
 61         val = other.val;
 62         ptr = other.ptr;//浅复制 
 63     }
 64     
 65     BDemo& operator=(const BDemo &rig)
 66     {
 67         val = rig.val;
 68         ptr = rig.ptr;//浅复制 
 69         return *this;
 70     }
 71     
 72     int get_ptr_val()
 73     {
 74         return *ptr;
 75     }
 76     void set_ptr(int v)
 77     {
 78         *ptr = v;
 79     }
 80 private:
 81     int val;
 82     int *ptr;
 83     
 84 };
 85 
 86 //====================智能指针start============
 87 class U_Ptr
 88 {
 89     friend class CDemo;
 90 private:
 91     int *ptr;
 92     size_t use;
 93     U_Ptr(int *p,int u)
 94     {
 95         this->ptr = p;
 96         use = u;
 97     }    
 98     ~U_Ptr()
 99     {
100         delete ptr;
101     }
102 } ;
103 
104 class CDemo
105 {//智能指针 
106 public:
107     CDemo(const int &p,int v)
108     {
109         ptr = new U_Ptr(new int(p),1);
110         val = v;
111     }
112     ~CDemo()
113     {
114         if(--ptr->use == 0)delete ptr;
115     }
116     
117     CDemo(const CDemo &other)
118     {
119         ++ptr->use;//多了一个对象使用 
120         val = other.val;
121         ptr = other.ptr;//浅复制 
122     }
123     CDemo& operator=(const CDemo &rig)
124     {
125         ++rig.ptr->use;
126         if(--ptr->use == 0)delete ptr;
127         
128         val = rig.val;
129         ptr = rig.ptr;//浅复制 
130         return *this;
131     } 
132     
133     void set_Ptr_val(int v)
134     {
135         *ptr->ptr = v;
136     }
137     
138     int get_ptr_val()
139     {
140         return *ptr->ptr;
141     }
142 private:
143     int val;
144     U_Ptr *ptr;
145 };
146 
147 void test_ShenCopy()
148 {
149     int prr = 20;
150     ADemo a(10,prr);
151     ADemo b = a;
152     cout<<"a = "<<a.get_ptr_val()<<endl;
153     cout<<"b = "<<b.get_ptr_val()<<endl;
154     cout<<"修改之后："<<endl;
155     a.set_ptr(40);
156     cout<<"a = "<<a.get_ptr_val()<<endl;
157     cout<<"b = "<<b.get_ptr_val()<<endl;
158 } 
159 void test_QianCopy()
160 {
161     
162     int prr = 40;
163     BDemo a(50,prr);
164     BDemo b = a;
165     cout<<"a = "<<a.get_ptr_val()<<endl;
166     cout<<"b = "<<b.get_ptr_val()<<endl;
167     cout<<"修改之后："<<endl;
168     b.set_ptr(80);
169     cout<<"a = "<<a.get_ptr_val()<<endl;
170     cout<<"b = "<<b.get_ptr_val()<<endl;
171 } 
172 
173 void test_smart()
174 {
175     int prr = 90;
176     CDemo a(100,prr);
177     CDemo b = a;
178     cout<<"a = "<<a.get_ptr_val()<<endl;
179     cout<<"b = "<<b.get_ptr_val()<<endl;
180     cout<<"修改之后："<<endl;
181     b.set_Ptr_val(180);
182     cout<<"a = "<<a.get_ptr_val()<<endl;
183     cout<<"b = "<<b.get_ptr_val()<<endl;
184 }
185 int main()
186 {
187     cout<<"深复制："<<endl;
188     test_ShenCopy();
189     cout<<endl<<"浅复制："<<endl;
190     test_QianCopy();
191     cout<<endl<<"智能指针："<<endl;
192     test_smart();
193     return 0;
194 }