add original source

source/listing_4.15.cpp

@@ -0,0 +1,43 @@
+struct card_inserted
+{
+    std::string account;
+};
+class atm
+{
+    messaging::receiver incoming;
+    messaging::sender bank;
+    messaging::sender interface_hardware;
+    void (atm::*state)();
+    std::string account;
+    std::string pin;
+    void waiting_for_card()
+    {
+        interface_hardware.send(display_enter_card());
+        incoming.wait()
+            .handle<card_inserted>(
+                [&](card_inserted const& msg)
+                {
+                    account=msg.account;
+                    pin="";
+                    interface_hardware.send(display_enter_pin());
+                    state=&atm::getting_pin;
+                }
+                );
+    }
+    void getting_pin();
+public:
+    void run()
+    {
+        state=&atm::waiting_for_card;
+        try
+        {
+            for(;;)
+            {
+                (this->*state)();
+            }
+        }
+        catch(messaging::close_queue const&)
+        {
+        }
+    }
+};