226 ________________________________ 7. Ad hoc 

23.     NDEBUG     -
,      .   
 ,    ,   -
        .  , -
,   ,       -
        .

24.   matrix_iterator ( )    -
,    vect_iterator   13  . 222.  
  successor () (), predecessor () (-
), reset () ()  item () ().  ,  -
   -  int r6w()   () 
int column () () (   7.3,  -
  . 195      matrix ).

25. ()  ,   rational   7.9, -
  -    ,  . 207.  ,  
    .      
  ,  ,      -
 .