text: // first.cpp
  
  /*    Copyright 2009 10gen Inc.
   *
   *    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.
   */
  
  /**
   * this is a good first example of how to use mongo from c++
   */
  
  #include <iostream>
  #include <cstdlib>
  
  #include "mongo/client/dbclient.h"
  
  using namespace std;
  
  void insert( mongo::DBClientConnection & conn , const char * name , int num ) {
      mongo::BSONObjBuilder obj;
      obj.append( "name" , name );
      obj.append( "num" , num );
      conn.insert( "test.people" , obj.obj() );
      std::string e = conn.getLastError();
      if( !e.empty() ) {
          cout << "insert failed: " << e << endl;
          exit(EXIT_FAILURE);
      }
  }
  
  int main( int argc, const char **argv ) {
  
      const char *port = "27017";
      if ( argc != 1 ) {
          if ( argc != 3 ) {
              cout << "need to pass port as second param" << endl;
              return EXIT_FAILURE;
          }
          port = argv[ 2 ];
      }
  
      mongo::DBClientConnection conn;
      string errmsg;
      if ( ! conn.connect( string( "127.0.0.1:" ) + port , errmsg ) ) {
          cout << "couldn't connect : " << errmsg << endl;
          return EXIT_FAILURE;
      }
  
      {
          // clean up old data from any previous tests
          mongo::BSONObjBuilder query;
          conn.remove( "test.people" , query.obj() );
      }
  
      insert( conn , "eliot" , 15 );
      insert( conn , "sara" , 23 );
  
      {
          mongo::BSONObjBuilder query;
          auto_ptr<mongo::DBClientCursor> cursor = conn.query( "test.people" , query.obj() );
          if (!cursor.get()) {
              cout << "query failure" << endl;
              return EXIT_FAILURE;
          }
  
          cout << "using cursor" << endl;
          while ( cursor->more() ) {
              mongo::BSONObj obj = cursor->next();
              cout << "\t" << obj.jsonString() << endl;
          }
  
      }
  
      {
          mongo::BSONObjBuilder query;
          query.append( "name" , "eliot" );
          mongo::BSONObj res = conn.findOne( "test.people" , query.obj() );
          cout << res.isEmpty() << "\t" << res.jsonString() << endl;
      }
  
      {
          mongo::BSONObjBuilder query;
          query.append( "name" , "asd" );
          mongo::BSONObj res = conn.findOne( "test.people" , query.obj() );
          cout << res.isEmpty() << "\t" << res.jsonString() << endl;
      }
  
  }
  