Update C++ client to use new INumberCruncher2 interface if available.

Author: Fredrik Orderud

MyClientCpp/Main.cpp

@@ -72,7 +72,16 @@ int main() {
 
         try {
             auto cruncher = server->GetNumberCruncher();
-            double pi = cruncher->ComputePi();
+            // try to cast to INumberCruncher2 to check if the new interface is implemented
+            MyInterfaces::INumberCruncher2Ptr cruncher2 = cruncher;
+            double pi = 0;
+            if (cruncher2) {
+                // use new interface
+                pi = cruncher2->ComputePi2();
+            } else {
+                // fallback to old interface
+                pi = cruncher->ComputePi();
+            }
             std::wcout << L"pi = " << pi << std::endl;
 
             auto callback = CreateLocalInstance<MyClient>();

MyClientCs/Program.cs

@@ -13,7 +13,16 @@ static void CommunicateWithServer()
 
             {
                 var cruncher = server.GetNumberCruncher();
-                double pi = cruncher.ComputePi();
+                double pi = 0;
+                try {
+                    // try to cast to INumberCruncher2 to check if the new interface is implemented
+                    var cruncher2 = (MyInterfaces.INumberCruncher2)cruncher;
+                    // use new interface
+                    pi = cruncher2.ComputePi2();
+                } catch (System.InvalidCastException) {
+                    // fallback to old interface
+                    pi = cruncher.ComputePi();
+                }
                 Console.WriteLine($"pi = {pi}");
 
                 // release reference to help GC clean up (not strctly needed)