no_obj.c

struct teacher {
  int id;
  char* name;
  int* classes;
  short parking_number
}

struct student {
  int id;
  char* name;
  float GPA;
  int* classes;
}

bool teacher_in_class(teacher* t) {
  // do logic
}

bool student_in_class(student* t) {
  // do logic
}