changed C++ samples due to OpenVINO style (#9463)

I'll merge this. We need to talk with someone who know openvino build system better than we to "use cmake function ov_ncc_style_check to perform such check automatically". As far as I can see, currently it used only in one place, so it is not common approach for openvino components

samples/cpp/classification_sample_async/classification_sample_async.h

@@ -45,7 +45,7 @@ DEFINE_string(d, "CPU", target_device_message);
 /**
  * @brief This function show a help message
  */
-static void showUsage() {
+static void show_usage() {
     std::cout << std::endl;
     std::cout << "classification_sample_async [OPTION]" << std::endl;
     std::cout << "Options:" << std::endl;

samples/cpp/classification_sample_async/main.cpp

@@ -40,22 +40,22 @@ using namespace ov::preprocess;
  * @param argv list of input arguments
  * @return bool status true(Success) or false(Fail)
  */
-bool ParseAndCheckCommandLine(int argc, char* argv[]) {
+bool parse_and_check_command_line(int argc, char* argv[]) {
     gflags::ParseCommandLineNonHelpFlags(&argc, &argv, true);
     if (FLAGS_h) {
-        showUsage();
+        show_usage();
         showAvailableDevices();
         return false;
     }
     slog::info << "Parsing input parameters" << slog::endl;
 
     if (FLAGS_m.empty()) {
-        showUsage();
+        show_usage();
         throw std::logic_error("Model is required but not set. Please set -m option.");
     }
 
     if (FLAGS_i.empty()) {
-        showUsage();
+        show_usage();
         throw std::logic_error("Input is required but not set. Please set -i option.");
     }
 
@@ -68,7 +68,7 @@ int main(int argc, char* argv[]) {
         slog::info << ov::get_openvino_version() << slog::endl;
 
         // -------- Parsing and validation of input arguments --------
-        if (!ParseAndCheckCommandLine(argc, argv)) {
+        if (!parse_and_check_command_line(argc, argv)) {
             return EXIT_SUCCESS;
         }