Update //third_party/protobuf to version 3.

third_party/protobuf/examples/add_person.cc

+// See README.txt for information and build instructions.
+
+#include <iostream>
+#include <fstream>
+#include <string>
+#include "addressbook.pb.h"
+using namespace std;
+
+// This function fills in a Person message based on user input.
+void PromptForAddress(tutorial::Person* person) {
+  cout << "Enter person ID number: ";
+  int id;
+  cin >> id;
+  person->set_id(id);
+  cin.ignore(256, '\n');
+
+  cout << "Enter name: ";
+  getline(cin, *person->mutable_name());
+
+  cout << "Enter email address (blank for none): ";
+  string email;
+  getline(cin, email);
+  if (!email.empty()) {
+    person->set_email(email);
+  }
+
+  while (true) {
+    cout << "Enter a phone number (or leave blank to finish): ";
+    string number;
+    getline(cin, number);
+    if (number.empty()) {
+      break;
+    }
+
+    tutorial::Person::PhoneNumber* phone_number = person->add_phones();
+    phone_number->set_number(number);
+
+    cout << "Is this a mobile, home, or work phone? ";
+    string type;
+    getline(cin, type);
+    if (type == "mobile") {
+      phone_number->set_type(tutorial::Person::MOBILE);
+    } else if (type == "home") {
+      phone_number->set_type(tutorial::Person::HOME);
+    } else if (type == "work") {
+      phone_number->set_type(tutorial::Person::WORK);
+    } else {
+      cout << "Unknown phone type.  Using default." << endl;
+    }
+  }
+}
+
+// Main function:  Reads the entire address book from a file,
+//   adds one person based on user input, then writes it back out to the same
+//   file.
+int main(int argc, char* argv[]) {
+  // Verify that the version of the library that we linked against is
+  // compatible with the version of the headers we compiled against.
+  GOOGLE_PROTOBUF_VERIFY_VERSION;
+
+  if (argc != 2) {
+    cerr << "Usage:  " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
+    return -1;
+  }
+
+  tutorial::AddressBook address_book;
+
+  {
+    // Read the existing address book.
+    fstream input(argv[1], ios::in | ios::binary);
+    if (!input) {
+      cout << argv[1] << ": File not found.  Creating a new file." << endl;
+    } else if (!address_book.ParseFromIstream(&input)) {
+      cerr << "Failed to parse address book." << endl;
+      return -1;
+    }
+  }
+
+  // Add an address.
+  PromptForAddress(address_book.add_people());
+
+  {
+    // Write the new address book back to disk.
+    fstream output(argv[1], ios::out | ios::trunc | ios::binary);
+    if (!address_book.SerializeToOstream(&output)) {
+      cerr << "Failed to write address book." << endl;
+      return -1;
+    }
+  }
+
+  // Optional:  Delete all global objects allocated by libprotobuf.
+  google::protobuf::ShutdownProtobufLibrary();
+
+  return 0;
+}