Thread: Decorator Help

Can somebody explain how this code works? Like main() and such.

Code:

#include <string>
#include <iostream>


using namespace std;

class Paragraph
{
public:
  Paragraph(const string& inInitialText) : mText(inInitialText) {}
        
  virtual string getHTML() const { return mText; }

protected:
  string mText;        
}; 

class BoldParagraph : public Paragraph
{
public:
  BoldParagraph(const Paragraph& inParagraph) :
    Paragraph(""), mWrapped(inParagraph) {}

  virtual string getHTML() const {
    return "<B>" + mWrapped.getHTML() + "</B>";
  }

protected:
  const Paragraph& mWrapped;
};

class ItalicParagraph : public Paragraph
{
public:
  ItalicParagraph(const Paragraph& inParagraph) :
    Paragraph(""), mWrapped(inParagraph) {}

  virtual string getHTML() const {
    return "<I>" + mWrapped.getHTML() + "</I>";
  }

protected:
  const Paragraph& mWrapped;
};



int main(int argc, char** argv)
{
  Paragraph p("A party? For me? Thanks!");

  // Bold
  cout << BoldParagraph(p).getHTML() << endl;

  // Bold and Italic
  cout << ItalicParagraph(BoldParagraph(p)).getHTML() << endl;
}

Output:

<B>A party? For me? Thanks!</B>
<I><B>A party? For me? Thanks!</B></I>