Работа со СТЕКОМ!!!!!!:)

#include <iostream>
 
class CharStack
{
    struct CharStackNode
    {
        char _character;
        CharStackNode *_next;
 
        CharStackNode(char character):
        _character(character),
        _next(0)
        {
        }
    };
 
public:
    CharStack():
    _top(0)
    {
    }
 
    CharStack(const CharStack &source):
    _top(0)
    {
        if (source._top != 0)
        {
            CharStackNode *i = source._top->_next;
            CharStackNode *j = new CharStackNode (source._top->_character);
 
            _top = j;
 
            while (i != 0)
            {
                j->_next = new CharStackNode (i->_character);
                
                i = i->_next;
                j = j->_next;
            }
        }
    }
 
    ~CharStack()
    {
        char dummy;
 
        while (pop(dummy));
    }
 
    void push(char character)
    {
        CharStackNode *new_elem = new CharStackNode (character);
 
        if (_top == 0)
        {
            _top = new_elem;
 
            return;
        }
 
        new_elem->_next = _top;
        _top = new_elem;
    }
 
    bool pop(char &character)
    {
        if (_top == 0)
            return false;
 
        CharStackNode *del_elem = _top;
 
        character = _top->_character;
        _top = _top->_next;
 
        delete del_elem;
 
        return true;
    }
 
private:
    CharStackNode *_top;
};
 
void input_char_stack(CharStack &char_stack)
{
    char character;
 
    std::cout << "Fill char stack" << std::endl
              << "Enter characters or \'Enter\' to exit:" << std::endl;
 
    std::cin.clear();
 
    while (std::cin >> character)
        char_stack.push(character);
}
 
size_t length_of_char_stack(CharStack &char_stack)
{
    CharStack copy(char_stack);
    char dummy;
    size_t len = 0;
 
    while (copy.pop(dummy))
        ++len;
 
    return len;
}
 
int main()
{
    CharStack stack1, stack2;
 
    input_char_stack(stack1);
    input_char_stack(stack2);
 
    std::cout << "Length of char stack 1: " << length_of_char_stack(stack1) << std::endl
              << "Length of char stack 2: " << length_of_char_stack(stack2) << std::endl;
 
    return 0;
}

std::cout << "Fill char stack" << std::endl
          << "Enter characters or \'Ctrl + Z\' and \'Enter\' to exit:" << std::endl;