c++ weak ptr解除指针循环引用。

#include<iostream>
#include<memory>
using namespace std;

class Point
{
public:
int value;
shared_ptr<Point> next;
weak_ptr<Point> weak_Next;
Point(int v):value(v){}
~Point(){cout << "delete-point-" << value << endl;}
};

//test 01--------------------------------------------
int main()
{
{
shared_ptr<Point> p1(new Point(1));
shared_ptr<Point> p2(new Point(2));
p1->next = p2;
p2->next = p1; //构成循环指向,导致最后不能释放p1/p2的空间
}

cout << "life end here" << endl;
system("pause");

return 0;
}

//test 02--------------------------------------------
/*
int main()
{
{
shared_ptr<Point> p1(new Point(1));
shared_ptr<Point> p2(new Point(2));
p1->next = p2;
p2->weak_Next= p1; //其中之一使用弱指针，就没有问题。
//从p2访问p1,需要锁定weakptr以生成sharedptr:
//p2->weak_Next.lock()->value;
}

cout << "life end here" << endl;
system("pause");

return 0;
}
*/