1 #include <iostream> 2 #include <cctype> 3  4 class WordCounter 5 { 6     enum class _state 7     { 8         STATE_INIT = 0, 9         STATE_IN_WORD,10         STATE_OUT_WORD,11     };12 public:13     static int count_words(const char* text);14 };15 16 int WordCounter::count_words(const char* text)17 {18     int counts = 0;19     _state state = _state::STATE_INIT;20     const char* it = text;21 22     for (; *it != ‘\0‘; it++)23     {24         switch (state)25         {26         case WordCounter::_state::STATE_INIT:27             if (isalpha(*it))28             {29                 state = _state::STATE_IN_WORD;30             }31             else32             {33                 state = _state::STATE_OUT_WORD;34             }35             break;36         case WordCounter::_state::STATE_IN_WORD:37             if (!isalpha(*it))38             {39                 state = _state::STATE_OUT_WORD;40                 //状态发生转换41                 counts++;42             }43             break;44         case WordCounter::_state::STATE_OUT_WORD:45             if (isalpha(*it))46             {47                 state = _state::STATE_IN_WORD;48             }49             break;50         default:51             break;52         }//switch53     }//for54     if (_state::STATE_IN_WORD == state)55     {56         counts++;57     }58     return counts;59 }60 61 int main(int argc, const char* argv[])62 {63     using namespace std;64     char* text = "   my  name is\r\n Percy!!this is BBC English";65     cout << text << ‘\n‘ << WordCounter::count_words(text) << endl;66     getchar();67     return 0;68 }