#include <iostream>
#include <algorithm>
#include <memory>
 
struct Node;
typedef std::shared_ptr<Node> NodePtr;
 
struct Node
{
    int value;
    NodePtr next;
    Node(int arg) : value(arg) {}
    ~Node() { std::cout << "Deleting " << value << '\n'; }
};
 
int main()
{
    // simple list population
    NodePtr head;
    NodePtr* p = &head;
    for (int i=1; i<=20; ++i)
    {
        p->reset(new Node(i));
        p = &(*p)->next;
    }
 
    // leaving now would be BAD.
 
    // proper cleanup. note that after the head reassignment
    //  only one outstanding shared pointer references the
    //  former head: victim. Two still reference the new list
    //  front: head and victim->next, and the latter will be
    //  released as soon as the while-scope exits and victim
    //  is deleted.
    while (head)
    {
        NodePtr victim = head;
        head = head->next;
    }
}

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