C++深拷贝和浅拷贝

using namespace std;
class A {
public:
    A(int a)
    {
        cout << "类型转换构造函数" << endl;
        b = new int[a];
    }public:
    int a;
    int* b;
};

int main() 
{
    A a(10);
    A b(a);//使用的是默认的拷贝构造函数
    cout << "a:" << (a.b) << "  b:" << (b.b);
    getchar();
    return 0;
}

//MemoryBlock.cpp
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
class MemoryBlock
{
public:
   explicit MemoryBlock(size_t length):_length(length),_data(new int[length])
   {
        cout << "In MemoryBlock(size_t). length = "
                << _length << "." << endl;
   }

   ~MemoryBlock()
   {
      cout << "In ~MemoryBlock(). length = "
                << _length << ".";
      if(_data!=nullptr)
      {
         cout << " Deleting resource.";
         delete[] _data;
      }
      cout<<endl;
   }

   MemoryBlock(const MemoryBlock& other):_length(other._length),
   _data(new int[other._length])
   {
      cout << "In MemoryBlock(const MemoryBlock&). length = "
                << other._length << ". Copying resource." << endl;
      copy(other._data,other._data+other._length,this->_data);
   }

   MemoryBlock& operator = (const MemoryBlock& other)
   {
      cout << "In operator=(const MemoryBlock&). length = "
                << other._length << ". Copying resource." << std::endl;
      if(this!=&other)
      {
         delete[] this->_data;
         this->_length = other._length;
         this->_data = new int[this->_length];
         copy(other._data,other._data + this->_length,this->_data);
      }
      return *this;
   }

   size_t Length() const
   {
      return _length;
   }

private:
   size_t _length;
   int* _data;
};

int main(int argv,char* argc[])
{
  // Create a vector object and add a few elements to it.
   vector<MemoryBlock> v;
   v.push_back(MemoryBlock(25));
   v.push_back(MemoryBlock(75));
   // Insert a new element into the second position of the vector.
   v.insert(v.begin() + 1, MemoryBlock(50));
   return 0;
}