// https://wokwi.com/projects/356609648316221441

class Box {
   public:
      static int objectCount;
      
      Box(int unused) {
         objectCount++;
      }

      Box() {
        objectCount++;
      }

      int report() {
         return objectCount;
      }
};

int Box::objectCount = 1000;

void objectTest() {

   Box Box1(7);
   Box Box2();          // add an argument here use the alternate constructor, it then compiles

  int wtf = Box1.report();
  Serial.println(wtf);

  wtf = Box2.report();
  Serial.println(wtf);

   return 0;
}

void setup() {
  Serial.begin(115200);
  Serial.println("h e l l o   t h e r e !\n");

  objectTest();
}

void loop() {
}

/*
classQuestion.ino: In function 'void objectTest()':
classQuestion.ino:28:14: error: request for member 'report' in 'Box2', which is of non-class type 'Box()'
   wtf = Box2.report();
              ^~~~~~

Error during build: exit status 1
*/