FBB::PtrIter(3bobcat)						   Error handler					     FBB::PtrIter(3bobcat)

NAME

       FBB::PtrIter - Iterator returning pointer when dereferenced

SYNOPSIS

       #include <bobcat/ptriter>

DESCRIPTION

       The  PtrIter  class  template implements an input iterator whose operator* returns the address of the element the iterator refers to.  Con-
       sider a std::unordered_map<std::string, DataType>. Its begin member returns an iterator whose operator*	returns  a  std::pair<std::string,
       DataType>  (const)  &. This is usually what you want, but now assume we want to display the map's contents, sorted by its keys. Sorting can
       simply be performed by defining a support vector containing pointers to the elements in the map, and then sorting the strings the  pointers
       point at.

       PtrIter is a tool that can be used to construct such a support vector, as shown in the EXAMPLE section.

       PtrIter is a class template requiring one template type parameter: Iterator, the iterator's type (e.g., vector<string>::iterator)

       PtrIter's  users  don't	have to specify PtrIter's template type. The function template ptrIter, when provided with an iterator returns the
       matching PtrIter object.

NAMESPACE

       FBB
       All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.

INHERITS FROM

       std::iterator<std::input_iterator_tag, ...>

FREE FUNCTION

       o      PtrIter<Iterator> ptrIter(Iterator const &iter):
	      this function template returns a PtrIter object for the function's Iterator argument. This function  template  simplyfies  the  con-
	      struction of a PtrIter as no template parameters need to be specified (see also the EXAMPLE section)

CONSTRUCTORS

       o      PtrIter(Iterator const &iter):
	      The  iter  parameter must be initialized with an existing input iterator, offering operator*, operator++, operator== and operator!=.
	      As PtrIter is a class template, its template type parameters must be specified when defining a PtrIter object. E.g.,

		  PtrIter<set<string>::iterator> PtrIter(mySet.begin());

	      The copy and move constructors are available.

OVERLOADED OPERATORS

       o      PtrType operator*() const:
	      the address of the entity the iterator refers to is returned;

       o      PtrIter &operator++():
	      the iterator is (pre)incremented to the next position;

       o      bool operator==(PtrIter const &other) const:
	      true is returned if the two iterators are equal;

       o      bool operator!=(PtrIter const &other) const:
	      true is returned if the two iterators are unequal; The copy and move assignment operators are available.

DEFINED TYPE

       PtrIter defines the following type:

       o      typedef decltype(&*Iterator()) PtrType:

MEMBER FUNCTIONS

       All members of std::iterator<std:::input_iterator_tag, ...> are available, as FBB::PtrIter inherits from this class.

EXAMPLE

       #include <algorithm>
       #include <unordered_map>
       #include <vector>
       #include <cstring>
       #include <iostream>

       #include <bobcat/ptriter>

       using namespace std;
       using namespace FBB;

       int main()
       {
	   cout << "Enter lines, the first word will be the map's key; "
						   "^D when done.
";

	   string key;
	   string line;
	   unordered_map<string, string> map;
	   while (cin >> key && getline(cin, line))    // fill the map
	       map[key] = line;
	   cout << '
';

					       // initialize a support
	   vector<decltype(&*map.begin())>     // vector, using ptrIter
	       support(ptrIter(map.begin()), ptrIter(map.end()));

					       // sort 'support'
	   typedef unordered_map<string, string>::value_type VT;
	   sort(support.begin(), support.end(),
	       [&](VT const *p1, VT const *p2)
	       {
		   return strcasecmp(p1->first.c_str(), p2->first.c_str()) < 0;
	       }
	   );

	   for(auto &element: support)	       // display sorted by key
	       cout << element->first << ' ' << element->second << '
';
       }

FILES

       bobcat/ptriter - defines the class interface

SEE ALSO

       bobcat(7)

BUGS

       None Reported.

DISTRIBUTION FILES

       o      bobcat_3.01.00-x.dsc: detached signature;

       o      bobcat_3.01.00-x.tar.gz: source archive;

       o      bobcat_3.01.00-x_i386.changes: change log;

       o      libbobcat1_3.01.00-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_3.01.00-x_*.deb: debian package holding the libraries, headers and manual pages;

       o      http://sourceforge.net/projects/bobcat: public archive location;

BOBCAT

       Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.

COPYRIGHT

       This is free software, distributed under the terms of the GNU General Public License (GPL).

AUTHOR

       Frank B. Brokken (f.b.brokken@rug.nl).

libbobcat1-dev_3.01.00-x.tar.gz 				     2005-2012						     FBB::PtrIter(3bobcat)