public bool RegistBook(ClassBook bookArg)
{
foreach (ClassBook e in book)
{
if (e.Equals(bookArg))
{
return true;
}
}
return false;
}
public void TakeBook(ClassBook bookArg)
{
if (RegistBook(bookArg))
{
bookArg.TakeBook();
}
}
public void GiveBook(ClassBook bookArg)
{
if (RegistBook(bookArg))
{
bookArg.GiveBook();
}
}