hi, I'm doing simple tests on all files in directory. But from some reason, sometimes, they behave wrongly? What's bad with my code?

using namespace std;


int main() {
 string s = "/home/";
   struct dirent * file;
   DIR * dir = opendir(s.c_str());
   while ((file = readdir(dir)) != NULL){
    struct stat * file_info = new (struct stat);
    stat(file->d_name,file_info);
    if ((file_info->st_mode & S_IFMT) == S_IFDIR)
     cout << "dir" << endl;
    else
     cout << "other" << endl;
   }
   closedir(dir);
}