【c++进阶】智能指针初体验

/*
 * c++进阶
 * 智能指针初体验
 * 小鱼号的代码日志
*/
#include <QCoreApplication>
#include<iostream>
#include<memory>
using namespace  std;
static void interfaceOfSharePrt();
class Object
{
public:
    Object(int id):m_id(id)
    {
     cout << "init obj id" << m_id << endl;
    }
    ~Object()
    {
     cout << "bye obj" << endl;
    }
    int getId() const
    {
        return m_id;
    }
private:
    int m_id;
};
typedef shared_ptr<Object> ObjectPtr;
void deleterOfObject(Object* obj)
{
   if(obj)
   {
       cout << "delete obj id " << obj->getId() << endl;
   }
   delete obj;
}
void print(ObjectPtr obj)
{
       cout << "print obj count " << obj.use_count()
            << "id "<< obj->getId() << endl;
}e
void printRef(const ObjectPtr& obj)
{
       cout << "print obj count " << obj.use_count()
            << "id "<< obj->getId() << endl;
}
void userDelete()
{
    ObjectPtr obj(new Object(2),deleterOfObject);
    ObjectPtr obj2 = obj;
}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    interfaceOfSharePrt();
    userDelete();
    return a.exec();
}

void interfaceOfSharePrt()
{
    ObjectPtr nullObj;
    cout << "ref count is " << nullObj.use_count() << endl;
    ObjectPtr obj(new Object(1));
    cout << "ref count is " << obj.use_count() << endl;
    ObjectPtr obj2(obj);
    cout << "ref count is " << obj.use_count() << endl;
    cout << "ref count is " << obj2.use_count() << endl;
    ObjectPtr obj3 = obj;
    cout << "ref count is " << obj.use_count() << endl;
    obj2.reset();
    cout << "ref count is " << obj.use_count() << endl;
    obj2 = nullptr;
    cout << "ref count is " << obj.use_count() << endl;
    ObjectPtr obj4;
    obj3.swap(obj4);
    cout << "ref count is " << obj.use_count() << endl;
    swap(obj3,obj4);
    cout << "ref count is " << obj.use_count() << endl;

    auto p = obj.get();
    if(p)
    {
         cout << "p id is " << p->getId() << endl;
    }

    if(obj)
    {
         cout << "obj id is " << obj->getId() << endl;
    }
    obj4 = nullptr;
    cout << "only one hold ptr" << obj.unique() << endl;
    print(obj);
    printRef(obj);
}