!= check on struct datatype

Projects Programming
12

gfvalvo:
One thing that comes to mind is I don't think you can 'malloc(sizeof(settings_type))' when the struct / class contains a method. You have to 'new' it.

I think you can.

struct Settings {
  int one;
  int two;
  float three;
  Settings () : one(10), two(20), three(30.0) {}
  bool operator==(Settings const & other) const {
    return one == other.one &&
           two == other.two &&
           abs(three - other.three) < 0.0001;
  }
  bool operator!=(Settings const &  other) const {
    return !(*this == other);
  }
};

const Settings defaultSet;
Settings dynamicSet;

void setup() {
  Serial.begin(250000);

  void* checker = malloc(sizeof(Settings));
  Settings* randomSet = reinterpret_cast<Settings*>(checker);

  if (*randomSet == defaultSet) {
    Serial.println(F("randomSet happens to be same as default"));
  } else {
    Serial.println(F("randomSet is different from default"));
  }
  free(checker);
  if (dynamicSet == defaultSet) {
    Serial.println(F("both start up the same"));
  }
  dynamicSet.one += 1;
  if (dynamicSet != defaultSet) {
    Serial.println(F("dynamicSet was changed"));
  }
}
void loop() {}

randomSet is different from default
both start up the same
dynamicSet was changed

Added: Using class with public: gives exactly the same result and behaviour.

Why would you want to leave out any initialization in the first place?