text: // Copyright 2020 Google LLC
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  // http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #include "google/cloud/spanner/client.h"
  #include <iostream>
  #include <stdexcept>
  
  int main(int argc, char* argv[]) try {
    if (argc != 4) {
      std::cerr << "Usage: " << argv[0]
                << " project-id instance-id database-id\n";
      return 1;
    }
  
    namespace spanner = ::google::cloud::spanner;
    spanner::Client client(
        spanner::MakeConnection(spanner::Database(argv[1], argv[2], argv[3])));
  
    auto rows =
        client.ExecuteQuery(spanner::SqlStatement("SELECT 'Hello World'"));
  
    for (auto const& row : spanner::StreamOf<std::tuple<std::string>>(rows)) {
      if (!row) throw std::runtime_error(row.status().message());
      std::cout << std::get<0>(*row) << "\n";
    }
  
    return 0;
  } catch (std::exception const& ex) {
    std::cerr << "Standard exception raised: " << ex.what() << "\n";
    return 1;
  }
  