C模仿命令

#include <boost/filesystem.hpp>
#include <boost/regex.hpp>  // also functional,iostream,iterator,String
namespace bfs = boost::filesystem;

struct match : public std::unary_function<bfs::directory_entry,bool> {
    bool operator()(const bfs::directory_entry& d) const {
        const std::string pat("filename_[0-5][34]");
        std::string fn(d.filename());
        return boost::regex_match(fn.begin(),fn.end(),boost::regex(pat));
    }
};

int main(int argc,char* argv[])
{
    transform_if(bfs::directory_iterator("."),bfs::directory_iterator(),std::ostream_iterator<std::string>(std::cout,"\n"),match(),mem_fun_ref(&bfs::directory_entry::fileName));
    return 0;
}

为简洁起见,我省略了transform_if()的定义.它不是标准功能,但应该直接实现.