Smart pointer 智能指针小总结

Smart pointer

line 58之后smart pointer里的计数已经是0，所以会真正释放它引用的对象，调用被引用对象的析构函数。如果继续用指针访问，会出现如下图的内存访问异常。所以说如果选择了用智能指针，就不要再试图用其他方式再去访问对象了。

 // sharedTest.cpp : Defines the entry point for the console application.
 //

 #include "stdafx.h"
 #include <boost/make_shared.hpp>
 #include <vector>
 //using namespace std;
 using namespace boost;

 #define SMART_PTR shared_ptr 

 class Based
 {
 protected:
     int a;
     char* pa;

 public:
     Based():a()
     {
         pa = new char[];
     }

     void Func(){ std::cout<<"Func "<<a<<std::endl; }
     virtual ~Based()
     {
         delete[] pa;
         std::cout<<"deconstrctor"<<std::endl;
     }
 };

 class Foo : public Based
 {
 private:
     int b;

 public:
     void Test()
     {
         this->b = ;
         this->pa[] = 'b';
         std::cout<<"Test(), b = "<<this->b<<"this->pa[0] =  "<<this->pa[]<<std::endl;
     }

     ~Foo(){ std::cout<<"~Foo()"<<std::endl;}
 };

 int main (int argc, const char * argv[])
 {
     Foo * pfoo = new Foo;

     std::cout<<"{"<<std::endl;
     {
       SMART_PTR<Foo> smart_foo(pfoo);
       smart_foo->Test();
     }
     std::cout<<"}"<<std::endl;

     pfoo->Test();

     return ;
 }