letter

  while (cin.eof() != true)　　//cin.eof判斷是否到達文件EOF，如果讀取到EOF return true，讀取到EOF則無法再次輸入 while (cin.fail() == true)   while (ch ！= EOF)   EOF ASCII 字符編碼 轉換成int unsigned signed int;      

>>阅读原文<<