public static void Main()
{
Inventory inv = Inventory.Instance;
inv[7043] = new Book("Professional C#", "Robinson");
inv[0871] = new Book("Instant UML", "Muller");
MemberManager mem = MemberManager.Instance;
mem[100] = new Member("Georgia", "5th Ave.", "New York");
mem[101] = new Member("William", "Park Lane", "London");
LoanManager loanmgr = LoanManager.Instance;
loanmgr.BorrowBook(7043, 100);
loanmgr.BorrowBook(0871, 101);
loanmgr.ReturnBook(7043);
loanmgr.ReturnBook(0871);
}