Fixed bug in custom input examples

examples/tutorial_api_cpp/4_asynchronous_loop_custom_input_and_output.cpp

@@ -76,6 +76,7 @@ public:
             auto datumsPtr = std::make_shared<std::vector<std::shared_ptr<UserDatum>>>();
             datumsPtr->emplace_back();
             auto& datumPtr = datumsPtr->at(0);
+            datumPtr = std::make_shared<UserDatum>();
 
             // Fill datum
             datumPtr->cvInputData = cv::imread(mImageFiles.at(mCounter++));

examples/tutorial_api_cpp/7_synchronous_custom_input.cpp

@@ -80,6 +80,7 @@ public:
                 auto datumsPtr = std::make_shared<std::vector<std::shared_ptr<UserDatum>>>();
                 datumsPtr->emplace_back();
                 auto& datumPtr = datumsPtr->at(0);
+                datumPtr = std::make_shared<UserDatum>();
 
                 // Fill datum
                 datumPtr->cvInputData = cv::imread(mImageFiles.at(mCounter++));

examples/tutorial_api_cpp/9_synchronous_custom_all.cpp

@@ -80,6 +80,7 @@ public:
                 auto datumsPtr = std::make_shared<std::vector<std::shared_ptr<UserDatum>>>();
                 datumsPtr->emplace_back();
                 auto& datumPtr = datumsPtr->at(0);
+                datumPtr = std::make_shared<UserDatum>();
 
                 // Fill datum
                 datumPtr->cvInputData = cv::imread(mImageFiles.at(mCounter++));