lockfree_push_listing7.2.cpp

#include <atomic>

template <typename T>
class lock_free_stack{
private:
    struct node{
        T data;
        node* next;
        node(T const& data_) : data(data_){}
    };
    std::atomic<node*> head;
public:
    void push(T const& data){
        node* const new_node =  new node(data);
        new_node->next = head.load();
        while(!head.compare_exchange_weak(new_node->next, new_node));
    }
    
    void pop(T& result){
        node* old_head = head.load();
        while(!head.compare_exchange_weak(old_head, old_head->next));
        result = old_head->data;
    }
};