Recursive Linked List

// 18/11/2006

/**
  * @author vishesh
  *
  * Recursive List Example
  * Demonstrate files and folder hierarchical structure
  **/


#include <iostream>
#include <string>
#include <list>

/** whiteSpace(unsinged int no)
  *
  * @param:
  *		unsigned int no:  factor which is multiplied by 2 give spaces
  * @return:
  *		char* which is basically consists of blank spaces
  *
  * This function is used in this program to leave some space
  * according to the depth of file while displaying output
  *
  */

inline char* whiteSpace(unsigned int no) {
	char *space = new char[no*2+2];
	for(unsigned int i=0; i<no*2+1; i++)
	{
		space[i] = ' ';
		space[i+1]='\0';
	}
	return space;
}

/** File class
  *
  * @param:
  *		none
  *		std::string name:  name of the file
  *
  * This class stores nothing but stores file names and
  * has a function to display that beautifully on monitor
  */
class File
{
protected:
	std::string name;				// name of file
public:
	File(){}						// just to satisfy compiler and inherited class
	File(std::string _name):name(_name){}	// store name of file
	~File(){}

	virtual void display(unsigned int depth) {

		// get no. of spaces according to depth
		char *spaces = whiteSpace(depth);	

		std::cout << "\n" << spaces << "File("	//display it
				  << depth <<"): " << name;
		delete[] spaces;			// free the memory taken by spaces
	}
};

/** Directory class, ingerited from File class
  *
  * @param:
  *		std::string name:  name of the dir
  *
  * This class nothing but stores files and
  * directories in a std::list class.
  */
class Directory:public File
{
protected:
	std::string  name;				// name of dir
	std::list<File*>	 files;		// so that it stores both files and dirs
public:
	Directory(std::string _name):name(_name) {}

	// destructor
	// delete everything, every file, every directory
	// and empty the list
	~Directory() {
		while(!files.empty())
		{
			delete files.back();
			files.pop_back();
		}
	}

	// display that
	void display(unsigned int depth=0) 
	{
		char *spaces = whiteSpace(depth);
		std::cout << "\n\n" << spaces << "Directory(" 
				  << depth  << "): " << name;

		for (std::list<File*>::iterator iter = files.begin(); 
			iter != files.end(); iter++) {
			// recursive call
			// depth to know how many spaces to leave
			(*iter)->display(depth+1);
		}

		std::cout << "\n";

		delete[] spaces;	// delete the memory taken by spaces
	}

	// add new item into list
	// takes pointer, so could take directory asd well as file
	void addFile(File *fle) {
		files.push_back(fle);
	}	
};

int main()
{
	Directory *root = new Directory("C");
	
	Directory *subDir1 = new Directory("Program Files");
	root->addFile(subDir1);

	Directory *subDir1D1 = new Directory("Winamp");
	subDir1D1->addFile(new File("winamp.exe"));
	subDir1D1->addFile(new File("winamptrat.exe"));
	subDir1D1->addFile(new File("somefile.dll"));
	subDir1->addFile(subDir1D1);

	Directory *subDir2 = new Directory("Develop");

	Directory *subDir2D1 = new Directory("C++");
	subDir2D1->addFile(new File("MinGW"));
	subDir2D1->addFile(new File("Visual C++"));
	subDir2D1->addFile(new File("Borland C++"));
	subDir2D1->addFile(new File("CodeBlocks"));
	subDir2->addFile(subDir2D1);

	Directory *subDir2D2 = new Directory("C#");
	subDir2D2->addFile(new File("Visual C#"));
	subDir2D2->addFile(new File("Borland C#"));
	subDir2->addFile(subDir2D2);

	Directory *subDir2D3 = new Directory("Web");
	subDir2D3->addFile(new File("HTML-Kit"));
	subDir2D3->addFile(new File("Dreamweaver"));
	subDir2D3->addFile(new File("Flash"));
	subDir2->addFile(subDir2D3);

	Directory *subDir2D3D1 = new Directory("Multimedia And Graphics");
	subDir2D3D1->addFile(new File("Flash"));
	subDir2D3D1->addFile(new File("Director"));
	subDir2D3D1->addFile(new File("Fireworks"));
	subDir2D3D1->addFile(new File("SVG"));
	subDir2D3->addFile(subDir2D3D1);

	root->addFile(subDir2);

	root->display();

	delete root;

	std::cin.get();
}