main.cpp:27:7: error: redefinition of 'class Smth'
 class Smth : public Object {
       ^~~~
In file included from main.cpp:17:0:
factory.h:41:7: note: previous definition of 'class Smth'
 class Smth : public Object {
       ^~~~
main.cpp: In function 'int main()':
main.cpp:44:5: error: redefinition of 'int main()'
 int main() {
     ^~~~
In file included from main.cpp:17:0:
factory.h:71:5: note: 'int main()' previously defined here
 int main() {
     ^~~~
main.cpp:48:17: error: 'class Factory' has no member named 'Register'
         factory.Register(class_id, my_new_smth_);
                 ^~~~~~~~