智能指针（二）

scoped_ptr有个特点是：所管理的对象的所有权不能被共享和转移，但是可以交换。

1.问题：如何做到不被共享和转移？
查看其源码,得知：私有了拷贝构造函数和赋值运算符重载函数

template<class T> class scoped_ptr // noncopyable
{
private:

    T * px;

    scoped_ptr(scoped_ptr const &);
    scoped_ptr & operator=(scoped_ptr const &);

    typedef scoped_ptr<T> this_type;

    void operator==( scoped_ptr const& ) const;
    void operator!=( scoped_ptr const& ) const;
    ...
 }

2.演示所有权交换

#include <iostream>
#include <string>
#include <boost/scoped_ptr.hpp>

using namespace std;

class Masterpiece
{
private:
    string name_;

public:
    Masterpiece(string name) : name_(name)
    {
        cout << "Construct Masterpiece " <<"<< "<< name_ << " >>"<< endl;
    }

    ~Masterpiece()
    {
        cout << "Destroyed Masterpiece " << "<< " << name_ << " >>" << endl;
    }
};

int main()
{
    cout << "=====Demo Begin=====" << endl;
    {
        boost::scoped_ptr<Masterpiece>masterpiece1(new Masterpiece("三国演义"));
        boost::scoped_ptr<Masterpiece> masterpiece2(new Masterpiece("西游记"));
        masterpiece1.swap(masterpiece2);
    }
    cout << "===== Demo End =====" << endl;

    cin.get();

    return 0;
}

说明:先构造的对象后析构，没有交换之前打印内容，对比交换之后的打印内容，即可验证

待续…