--- a/sources/range.h Wed Jul 20 22:56:16 2016 +0300 +++ b/sources/range.h Fri Jul 22 17:50:00 2016 +0300 @@ -108,6 +108,11 @@ return m_b; } + T step() const + { + return m_step; + } + void check_bounds() { if (m_b < m_a)