C++ 遍历中文字符串 UTF-8

1. 下载utfcpp并添加到项目https://github.com/nemtrif/utfcpp
2. 代码示例 https://www.v2ex.com/amp/t/331843 引自QAPTEAWH

   for (auto it = str.begin(), it2 = str.begin(); it2 != str.end(); ) {
       utf8::next(it2, str.end());
       while (it < it2) {
           cout << *it;
           ++it;
       }
       cout << endl;
   }