FBB::Ranger(3bobcat) for-loop iterators FBB::Ranger(3bobcat)

FBB::Ranger - generalizes ranges for range-based for-loops

#include <bobcat/ranger>

The Ranger class template defines ranges that can be used with range-based for-loops. The standard range-based for-loop requires for its range-specificiation an array or an iterator range as offered by, e.g., containers (through their begin and end members). Ranges defined by a pair of pointers or by a subrange defined by iterator expressions cannot currently be used in combination with range-based for-loops.

Ranger extends the applicability of range-based for-loops by turning pairs of pointers, an initial pointer and a pointer count, or a pair of iterators into a range that can be used by range-based for-loops.

Ranger is a class template requiring one template type parameter: Iterator, an iterator or pointer type reaching the data when dereferenced.

Ranger’s users don’t have to specify Ranger’s template type. The function template ranger returns the appropriate Ranger object.

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

When using the following free functions, any (subrange) of iterators or pointers can be used. With iterators subranges of reverse iterators can also be specified. The EXAMPLE section below illustrates the use of the ranger function templates.

Ranger<Iterator> ranger(Iterator &&begin, Iterator &&end):
this function template returns a Ranger object for the (sub)range defined by two (reverse) iterators;
Ranger<Iterator> ranger(Iterator &&begin, size_t count):
this function template returns a Ranger object for the (sub)range defined by the (reverse) iterator range begin and begin + count;
Ranger<Data *> ranger(Data *begin, Data *end):
this function template returns a Ranger object for the (sub)range defined by the two pointers begin and end;
Ranger<Data *> ranger(Data *begin, size_t count):
this function template returns a Ranger object for the (sub)range defined by the two pointers begin and begin + count.

Below, Iterator refers to the Ranger class template’s type parameter. Although named ’Iterator’ it can also be a pointer to some data type (e.g., std::string *).

Ranger(Iterator const &begin, Iterator const &end):
A Ranger object can be passed as range-specifier in a range-based for-loop. All elements defined by the range will subsequently be visited by the range-based for-loop.

Copy and move constructors (and assignment operators) are available.

Iterator const &begin() const:
returns (a copy of) the begin iterator passed to the Ranger’s constructor. Note that if Iterator was a pointer type (like int *) the data to which the iterator returned by begin() can actually be modified, as the member’s return type (using int * for Iterator) becomes int * const &, so a reference to a constant pointer to an int. This is perfectly OK: if the data themselves should be immutable, then the data type must be defined as int const, which is automatically the case when passing int const * data. See the EXAMPLE section for an illustration.
Iterator const &end() const:
returns (a copy of) the end iterator passed to the Ranger’s constructor. If reverse iterators are passed to Ranger’s constructor, then the begin and end members return reverse iterators. Since the intended use of Ranger objects is to define a range for range-base for-loops, members like rbegin and rend can be omitted from Ranger.

#include <vector>
#include <iostream>
#include <bobcat/ranger>
using namespace std;
using namespace FBB;
int main()
{
    vector<int> iv {1, 2, 3, 4, 5};
                                    // display and modify a subrange
    for(auto &el: ranger(iv.rbegin() + 1, iv.rend() - 1))
        cout << el++ << ’ ’;
    cout << ’\n’;
                                    // display a reversed range
    for(auto &el: ranger(iv.rbegin() + 1, iv.rend() - 1))
        cout << el << ’ ’;
    cout << ’\n’;
                                    // same: display using a count
    for(auto &el: ranger(iv.rbegin() + 1, 3))
        cout << el << ’ ’;
    cout << ’\n’;
    int intArray[] = {1, 2, 3, 4, 5};
                                    // display and modify elements
                                    // in a pointer-based range
    for(auto &el: ranger(intArray + 1, intArray + 3))
        cout << el++ << ’ ’;
    cout << ’\n’;
                                    // data now modified
    for(auto &el: ranger(intArray + 1, intArray + 3))
        cout << el << ’ ’;
    cout << ’\n’;
                                    // using a count rather than an
                                    // end-pointer
    for(auto &el: ranger(intArray + 1, 3))
        cout << el << ’ ’;
    cout << ’\n’;
    int const constInts[] = {1, 2, 3, 4, 5};
                                    // data can’t be modified
    for(auto &el: ranger(constInts + 1, constInts + 3))
        cout << el << ’ ’;
    cout << ’\n’;
}

bobcat/ranger - defines the class interface

bobcat(7), reverse(3bobcat)

None Reported.

https://fbb-git.gitlab.io/bobcat/: gitlab project page;
bobcat_6.06.02-x.dsc: detached signature;
bobcat_6.06.02-x.tar.gz: source archive;
bobcat_6.06.02-x_i386.changes: change log;
libbobcat1_6.06.02-x_*.deb: debian package containing the libraries;
libbobcat1-dev_6.06.02-x_*.deb: debian package containing the libraries, headers and manual pages;

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

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

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

2005-2024 libbobcat-dev_6.06.02