// sstack.h: simple string stack

#ifndef _sstack_h
#define _sstack_h

#include <string>

class StringStack {
public:
    // construct empty stack
    StringStack();
    // return true if stack empty, false otherwise
    bool empty() const;
    // push new_item on top of stack
    void push(std::string new_item);
    // remove top element of stack and return it; undefined if stack empty
    std::string pop();
    // remove all items from the stack
    void clear();
private:
    class StackNode {
        std::string _item;
        StackNode *_next;
    public:
        StackNode(std::string value, StackNode *n = nullptr) 
            : _item(value), _next(n) 
        { }
        std::string item() const { return _item; }
        StackNode *next() const { return _next; }
        void setNext(StackNode *n) { _next = n; }
    };
    // TODO: declare the pointer for the stack of nodes:

};

#endif