388                                       .   

  .   -   
   ,       -
: friend class _.

   :

class tweedledum {

friend int tweedledee::Cheshire();

};

class node {

friend class tree;

//-  tree    node

} ;

  complexc.cpp

class complex {

friend complex operator+(complex);

C.12.4.  this

  this      .  
    -.   this
     .    ,
    clock     clock* const this. -
  C++   ,   ,
    this.   , 
 this  .    .  7.5, 
 ,  . 199 (  clock.cpp).

. 12.5.  

      .   -
   operator.    ,   print,
    ,   ,   -
, , +,    .   -
    '    ,   
 .      .

      -, 
 ,   ,     -
.      -,  -

' ,       
,  =+.         
=+(, ) , , c=plus(a, b), , ,   .
 . .