// BookQuantity Check public bool bookQuantityCheck(string bookQuantity) { if (string.IsNullOrWhiteSpace(bookQuantity)) { print.bookQuantityOverMessage(); return(true); } if (stringCheck(bookQuantity, 5)) { print.ErrorMessage(); return(true); } if (bookQuantity.Length == 0 || bookQuantity.Length >= 3) { print.ErrorMessage(); return(true); } return(false); }