How do I make this program in polymorphic form?

[LemonHappy]

This is the code I'm working on

#include <iostream> 
using namespace std;

class store {
protected:
	int x;
public:
	char shelf()
	{
		char x;
		cin >> x;
		switch (x) {
		case 'a':
			cout << "Water Ghosts\n" << endl;
			break;
		case 'b':
			cout << "Black Water\n" << endl;
			break;
		case 'c':
			cout << "Gathering of Waters\n" << endl;
			break;
		default: cout << "sigh!\n" << endl;
		}
		return x;
	};
};

class mother : public store {
public:
	void shelf()
	{
		cout << "Pick abook " << endl;
	}
};

class daughter : public mother {
public:
	void books()
	{
		cout << "This ia a great book\n";
	}
};


int main()
{
	store bookshelf;
	mother selectbook;
	selectbook.shelf();
	char option = bookshelf.shelf();
	daughter book;
	book.books();
	system("pause");
}

[Bdanielz]

Sorry, who is a mother? Who is a daughter?