source: doc/papers/general/evaluation/cpp-stack.hpp@ aec2c022

#pragma once
#include <utility>

template<typename T> struct stack {
        struct node {
                T value;
                node * next;
                node( const T & v, node * n = nullptr ) : value( v ), next( n ) {}
        };
        node * head;

        void copy( const stack<T> & o ) {
                node ** cr = &head;
                for ( node * nx = o.head; nx; nx = nx->next ) {
                        *cr = new node{ nx->value }; /***/
                        cr = &(*cr)->next;
                }
                *cr = nullptr;
        }

        void clear() {
                for ( node * nx = head; nx; ) {
                        node * cr = nx;
                        nx = cr->next;
                        delete cr;
                }
                head = nullptr;
        }

        stack() : head( nullptr ) {}
        stack( const stack<T> & o ) { copy( o ); }
        ~stack() { clear(); }

        stack & operator=( const stack<T> & o ) {
                if ( this == &o ) return *this;
                clear();
                copy( o );
                return *this;
        }

        bool empty() const {
                return head == nullptr;
        }

        void push( const T & value ) {
                head = new node{ value, head };  /***/
        }

        T pop() {
                node * n = head;
                head = n->next;
                T v = std::move( n->value );
                delete n;
                return v;
        }
};