智能指针手写

#include<bits/stdc++.h>
#define ll long long
using namespace std;
template<typename T>
class share_ptr{
    private:
        T* _ptr;
        int* cnt;

    public:
        share_ptr():cnt(new int(1)),_ptr(new T){}
        share_ptr(T* p) : cnt(new int(1)), _ptr(p) {}
        share_ptr(share_ptr<T>& ptr):cnt(&(++*ptr.cnt)),_ptr(ptr._ptr){}
        T& operator*()
        {
            return *_ptr;
        }
        T* operator->()
        {
            return _ptr;
        }
        share_ptr<T>& operator=(share_ptr<T>& other)
        {
            if(this==&other)
            {
                return *this;
            }
            ++*other.cnt;

            if(cnt!=nullptr&&--*cnt==0)
            {
                delete _ptr;
                delete cnt;
            }
            _ptr=other._ptr;
            cnt=other.cnt;
            return *this;
        }
        ~share_ptr(){
               if(cnt!=nullptr&&--*cnt==0)
               {
                    delete cnt;
                    delete _ptr;
               }
        }
        int getRef(){
            return *cnt;
        }


};
int main()
{
    share_ptr<string> pstr(new string("abc"));
    cout << "pstr:"  << pstr.getRef()  << " " << *pstr  << endl;

    share_ptr<string> pstr2(pstr);
    cout << "pstr:"  << pstr.getRef()  << " " << *pstr  << endl;
    cout << "pstr2:" << pstr2.getRef() << " " << *pstr2 << endl;

    share_ptr<string> pstr3(new string("hao"));
    cout << "pstr3:" << pstr3.getRef() << " " << *pstr3 << endl;

    pstr3 = pstr2;
    cout << "pstr:"  << pstr.getRef()  << " " << *pstr  << endl;
    cout << "pstr2:" << pstr2.getRef() << " " << *pstr2 <<  endl;
    cout << "pstr3:" << pstr3.getRef() << " " << *pstr3 << endl;


    return 0;
}

运行结果：