計概筆記12

<計概筆記8-2>

˙Abstraction抽象化:
  -the concept of abstraction means:
   1. You know what a data type can do.
   2. How it is done is hidden.
  -user : in this context does not necessarily refer to a human
 
˙ADT(Abstraction Data Type)
  1.Declaration宣告 of data
  2.Declaration of operations
  3.Encapsulation封裝 of data and operations

˙static v.s dynamic structures
  -構成資料的抽象型態時的一個重要差異點是 : 結構的形狀及大小是否隨時間而改變(靜態 or 動態)

˙Pointer : is a storage area that contains such an encoded address.
                is used to record the location where data items are stored.
  - another name for a program counter程式計數器 is instruction pointer指令指標.

˙儲存陣列
  1.同質陣列 :
    - 分為 : 1.row major order以列為主次序
               2.column major order以行為主次序
    - 必須先在記憶體中保留和陣列相當大小的連續區塊
  2.異質陣列 :
    - store each component in a separate location and then link them together by means of pointers.
    - is especially useful in those cases in which the size of the array's components is dynamic變動的.