Using c++ typedef/using type alias

I am reading C++ primer book and completely don't understand one line:

 using int_array = int[4]; 
 typedef int int_array[4]; // This line
 for (int_array *p = ia; p != ia + 3; ++p) {
      for (int *q = *p; q != *p + 4; ++q)
          cout << *q << ' '; cout << endl;
 }

Ok typedef is same as using. Does it mean int[4][4] is now int and how to understand that? And what type is int_array in for loop?

Thanks