Add helloworld example in c++
diff --git a/cpp/helloworld/greeter_client.cc b/cpp/helloworld/greeter_client.cc
new file mode 100644
index 0000000..4a51f5e
--- /dev/null
+++ b/cpp/helloworld/greeter_client.cc
@@ -0,0 +1,91 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include <grpc/grpc.h>
+#include <grpc++/channel_arguments.h>
+#include <grpc++/channel_interface.h>
+#include <grpc++/client_context.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/status.h>
+#include "helloworld.pb.h"
+
+using grpc::ChannelArguments;
+using grpc::ChannelInterface;
+using grpc::ClientContext;
+using grpc::Status;
+using helloworld::HelloRequest;
+using helloworld::HelloReply;
+using helloworld::Greeter;
+
+class GreeterClient {
+ public:
+  GreeterClient(std::shared_ptr<ChannelInterface> channel)
+      : stub_(Greeter::NewStub(channel)) {}
+
+  std::string SayHello(const std::string& user) {
+    HelloRequest request;
+    request.set_name(user);
+    HelloReply reply;
+    ClientContext context;
+
+    Status status = stub_->sayHello(&context, request, &reply);
+    if (status.IsOk()) {
+      return reply.message();
+    } else {
+      return "Rpc failed";
+    }
+  }
+
+  void Shutdown() { stub_.reset(); }
+
+ private:
+  std::unique_ptr<Greeter::Stub> stub_;
+};
+
+int main(int argc, char** argv) {
+  grpc_init();
+
+  GreeterClient greeter(
+      grpc::CreateChannel("localhost:50051", ChannelArguments()));
+  std::string user("world");
+  std::string reply = greeter.SayHello(user);
+  std::cout << "Greeter received: " << reply << std::endl;
+
+  greeter.Shutdown();
+
+  grpc_shutdown();
+}