/// <summary> /// Override of Equals(object obj) method /// </summary> /// <param name="obj"></param> /// <returns>Equality result</returns> public override bool Equals(object obj) { if (obj == null) { return(false); } if (ReferenceEquals(obj, this)) { return(true); } Book book = obj as Book; if (book == null) { return(false); } if (book.GetHashCode() != this.GetHashCode()) { return(false); } return(book.ISBN == this.ISBN); }