My class of a item of furniture, and sofa with item inherited is below:

Code:
#include <iostream>
#include <fstream>

using namespace std;

class Item

{
	public:
		string modelName;
		int	numberInstock;

		Item(){}			
		Item(int name){}

		virtual void UpdateNumber(){}
		virtual void printDetails()
		{

		}

};

class Sofa:public Item

{
	
public:

	Sofa (string a , string b) : Item () 
	{
	fabric = a;
	colour = b;
	}

	Sofa () : Item ()
	{
		cout << "Enter type of fabric: ";                 //// This constructor
		cin >> fabric;
		cout << endl << "Enter colour of fabric: ";
		cin >> colour;
		cout << endl;
	}

	string fabric;
	string colour;
	
	void printDetails(){}
};
The constructor which i have marked "This constructor" is the one I am working on. I want a constructor with no parameters which allows the user to enter data members interactively. How is this done?

Thanks