stack.cpp

#ifndef ALGORITHM_ADT_STACK_H_
#define ALGORITHM_ADT_STACK_H_ 1

namespace algorithm
{
namespace adt
{

template<class Element>
    class Stack
    {
    private:
        struct Node
        {
            Element     element;
            Node*       next;

            Node(const Element& element)
            : element(element), next(nullptr)
            { }
        };

        Node*       top_;
        int         size_;

        static
        Node*
        CreateNode(const Element& element)
        { return new Node(element); }

        static
        void
        DestroyNode(Node* node)
        { if(node != nullptr) delete node; }

    public:
        Stack(void)
        : top_(nullptr), size_(0)
        { }

        ~Stack(void)
        { while(! empty()) pop(); }


        /* element access */
        Element&
        peek(void)
        { return top_->element; }


        /* capacity */
        inline bool
        empty(void) const
        { return top_ == nullptr; }

        inline int
        size(void) const
        { return size_; }


        /* modifiers */
        void
        push(const Element& element)
        {
            Node* node = CreateNode(element);

            if(! empty())
                node->next = top_;
            top_ = node;
            ++size_;
        }

        void
        pop(void)
        {
            if(! empty())
            {
                Node* node = top_;
                top_ = node->next;
                --size_;

                DestroyNode(node);
            }
        }
    };

} /* ns:adt */
} /* ns:algorithm */

#endif /* ! ALGORITHM_ADT_STACK_H_ */