如何访问重复捕获组的所有匹配，而不仅仅是最后一个？

My code is:

我的代码是:

#include <boost/regex.hpp>
boost::cmatch matches;
boost::regex_match("alpha beta", matches, boost::regex("([a-z])+"));
cout << "found: " << matches.size() << endl;
#include <boost/regex.hp