std::ctype <char> :: ctype

From cppreference.com
Defined in header <locale>
explicit ctype ( const mask * tbl = 0 , bool del = false , std:: size_t refs = 0 ) ;

Creates a std:: ctype < char > facet and forwards the starting reference count refs to the base class constructor, locale::facet::facet() .

If tbl is null, classic_table() is used by all classification member functions. Otherwise, tbl must be a pointer to the first element of an array of masks, at least std:: ctype < char > :: table_size in size, and that array is used by all of this facet's classification member functions.

If del is true , it is assumed that the array was allocated with new [ ] , and the destructor of this facet will call delete [ ] tbl .

Parameters

tbl - classification table to use or a null pointer
del - indicator whether the table needs to be deleted
refs - starting reference count

Example