  DDscat.C++ 7.3.0 is a freely available open-source C++ software package
applying the "discrete dipole approximation" (DDA) to calculate scattering and
absorption of electromagnetic waves by targets with arbitrary geometries and a
complex refractive index. DDscat.C++ is a clone of well known DDscat Fortran-90
software. We refer to DDscat as to the parent code in this document. Versions
7.3.0 of both codes have the identical functionality but the quite different
implementation. Started as a teaching project, the DDscat.C++ code differs from
the parent code DDscat in programming techniques and features, essential for
C++ but quite seldom in Fortran.
  As DDscat.C++ in its current version is just a clone, usage of DDscat.C++ for
electromagnetic calculations is the same as of DDscat. Please, refer to "User
Guide for the Discrete Dipole Approximation Code DDSCAT 7.3" to start using the
code(s).
  This document consists of two parts. In the first part we present Quick start
guide for users who want to begin to use the code. Only differencies between
DDscat.C++ and DDscat are explained. The second part of the document explains
programming tips for the persons who want to change the code, to add the
functionality or help the author with code refactoring and debugging.
