programming style updates

src/atom.cpp

@@ -89,7 +89,7 @@ are updated by the AtomVec class as needed.
  *
  * \param  _lmp  pointer to the base LAMMPS class */
 
-Atom::Atom(LAMMPS *_lmp) : Pointers(_lmp)
+Atom::Atom(LAMMPS *_lmp) : Pointers(_lmp), atom_style(nullptr), avec(nullptr), avec_map(nullptr)
 {
   natoms = 0;
   nlocal = nghost = nmax = 0;
@@ -272,9 +272,6 @@ Atom::Atom(LAMMPS *_lmp) : Pointers(_lmp)
   unique_tags = nullptr;
   reset_image_flag[0] = reset_image_flag[1] = reset_image_flag[2] = false;
 
-  atom_style = nullptr;
-  avec = nullptr;
-
   avec_map = new AtomVecCreatorMap();
 
 #define ATOM_CLASS