How to concatenate split files without new line and replicate original file?

void merge(std::string& filesPath,   std::string& outPutFilePath) {

       namespace fs = std::filesystem;
       std::set<fs::path> files_to_merge;
       std::ofstream merged_file;
       fs::path split_path = fs::path(filesPath);
       for (const auto& file : fs::directory_iterator(split_path)) {
            files_to_merge.insert((fs::path)file);
            }
  
      std::ofstream ofile(outPutFilePath,std::ios::out|std::ios::app|std::ios::binary);
      ofile.unsetf(std::ios_base::skipws);
      for (auto& file : files_to_merge) {
      std::ifstream ifile(file, std::ios::in |  std::ios::binary);
      if (!ifile.is_open())
         {
          throw invalid_file("could not read file: ");
          break;
        }
     ifile.unsetf(std::ios_base::skipws);
     std::copy(std::istream_iterator<char> (ifile),
          std::istream_iterator<char>(),
          std::ostream_iterator<char> (ofile));
    //ofile << ifile.rdbuf();
      }

    } 

split_path is path to splits of bigger file. The code actually merges. The problem is it inserts a new line between 2 file parts.The insertion of new line may not problem for human beings. But when the merged file is encrypted file, the decryption algorithm fails due the inserted new line[s]. Is there a way to replicate original file when merging?