Added some more examples

cpp/zmq/req-rep/Makefile

@@ -0,0 +1,12 @@
+server : server.cpp
+	g++  -o server server.cpp -lzmq
+server_arg: server_arg_port.cpp 
+	g++ -o server_arg server_arg_port.cpp -lzmq
+client : client.cpp
+	g++ -o client client.cpp -lzmq
+client_connect_to_many : client_connect_multiple_server.cpp
+	g++ -o client_connect_to_many client_connect_multiple_server.cpp -lzmq
+
+all: server server_arg client client_connect_to_many client
+clean:
+	rm -f server server_arg client client_connect_to_many client

cpp/zmq/req-rep/client_connect_multiple_server.cpp

@@ -0,0 +1,40 @@
+#include <zmq.hpp>
+#include <string>
+#include <iostream>
+#include <unistd.h>
+
+using std::cerr;
+using std::cout;
+using std::endl;
+
+int main (int argc, char *argv[])
+{
+  if (argc < 2){
+      cerr << "Usage: " << argv[0] << " server1-port server2-port ... ";
+      exit(1);
+  }
+
+  zmq::context_t context (1);
+  zmq::socket_t socket (context, ZMQ_REQ);
+
+  int i  = 1;
+  char transport[128];
+
+  while (i < argc) {
+    snprintf(transport, 128, "tcp://127.0.0.1:%s", argv[i++]);
+    socket.connect(transport);
+  }
+
+  while (true){
+      zmq::message_t request (1024);
+      memcpy ((void *) request.data (), "Hello", 6);
+      socket.send (request);
+      zmq::message_t reply;
+      socket.recv (&reply);
+      cout << "Received " << (char *)reply.data() << endl;
+      sleep(1);
+  }
+  socket.close();
+  context.close();
+  return 0;
+}

cpp/zmq/req-rep/server.cpp

@@ -1,7 +1,6 @@
 #include <zmq.hpp>
 #include <string>
 #include <iostream>
-#include <unistd.h>
 int main ()
 {
   zmq::context_t context (1);

cpp/zmq/req-rep/server_arg_port.cpp

@@ -0,0 +1,39 @@
+#include <zmq.hpp>
+#include <string>
+#include <iostream>
+
+using std::cerr;
+using std::cout;
+using std::endl;
+
+int main (int argc, char *argv[])
+{
+  if (argc != 2) {
+    cerr << argv[0] << " " << "bind-port" << endl;
+    exit(1);
+  }
+
+  char transport[255] = "";
+  zmq::context_t context (1);
+  zmq::socket_t socket (context, ZMQ_REP);
+  snprintf(transport, 255, "tcp://*:%s", argv[1]);
+  socket.bind (transport);
+
+  char response[512]; 
+  memset(response, 0, 512);
+  snprintf(response, 512, "Response from server lisetning on %s", argv[1]);
+  int i = strlen(response);
+  int times = 0;
+
+  while (true){
+      zmq::message_t request;
+      socket.recv (&request);
+      zmq::message_t reply (512);
+      snprintf(response + i , 512, " #%d", times++);
+      memcpy ((void *) reply.data (), response, strlen(response));
+      socket.send (reply);
+  }
+  socket.close();
+  context.close();
+  return 0;
+}