args.cpp

#include <iostream>
#include <stdexcept>

class Note {
public:
  int PublicField;
  std::string GetPrivateField() {
    return privateField;
  }
  void SetPrivateField(const std::string& field) {
    ensurePrivateFieldLength(field);
    privateField = field;
  }
private:
  void ensurePrivateFieldLength(const std::string& field) {
    if(field.length() == 0) {
      throw new std::invalid_argument("Empty private field given!");
    }
  }
  std::string privateField;
};

static Note NewNote(const std::string& field) {
  Note inst{};
  inst.PublicField = 2;
  inst.SetPrivateField(field);
  return inst;
}

int main(int argc, char** argv) {
  std::cout << "You have given " << argc << " arguments:" << std::endl;
  for (int i = 0; i < argc; ++i) 
  {
      std::cout << argv[i] << std::endl;
  }
  
  try {
    auto note = NewNote("my note");
    std::cout << note.PublicField << std::endl;
    std::cout << note.GetPrivateField() << std::endl;
    
    Note* notepointer;
    notepointer = &note;
    std::cout << notepointer->PublicField << std::endl;
    std::cout << notepointer->GetPrivateField() << std::endl;
  } catch(std::invalid_argument& ex) {
     return 1; 
  }
  
  return 0;
}