根据题意先对书的信息进行定义，然后利用this对书的信息进行初始化。定义四个函数，分别为reserve，ableToBorrow，borrow，cancelReservation，return，实现图书馆预订书，借书取消预订的书，还书的功能。-According to the problem of book information are defined, and then use this to initialize the book information. The definition o