#include <iostream>
#include <vector>
#include <string>

class TextElement {
public:
    virtual std::string render() = 0 ;
    virtual void add(TextElement* t) = 0 ;
};

class ComposedElement : public TextElement {
    std::string _begin;
    std::string _end;
    std::vector<TextElement*> _textElement;
public:
    ComposedElement(std::string begin, std::string end) : _begin(begin), _end(end) {}
    std::string render() override {
        std::string rendered = _begin;
        for (size_t i = 0; i < _textElement.size(); i++)
            rendered += "\n" + _textElement[i]->render();
        return rendered + "\n" + _end;
    }
    void add(TextElement* t) override { _textElement.push_back(t); }
};

class Page : public ComposedElement {
public:
    Page() : ComposedElement("<page>", "</page>") {}
};

class Paragraph : public ComposedElement {
public:
    Paragraph() : ComposedElement("<p>", "</p>") {}
};

class Span : public TextElement{
    std::string _text;
public:
    Span(std::string text) : _text(text) {}
    std::string render() { return "<span>" + _text + "</span>"; }
    void add(TextElement* t) { throw "unsupported operation"; }
};


class Image : public TextElement{
    std::string _src;
public:
    Image(std::string src) : _src(src) {}
    std::string render() { return "<img src=" + _src + "/>"; }
    void add(TextElement* t) { throw "unsupported operation"; }
};

int main() {
    Page page;
    Paragraph p1, p2;
    Span s1("TEXT"), s2("TEXT");
    Image i("www.alfredo.com");
    p1.add(&s1);
    p1.add(&s2);
    p2.add(&i);
    page.add(&p1);
    page.add(&p2);
    std::cout << page.render();
    return 0;
}