Using C++14 and C++11 algorithms

C++11 has a bunch of new cool algorithms in <algorithm> header. C++14 has even more algorithms. If you're stuck with the pre-C++11 compiler, you have to write those from scratch. For example, if you wish to output characters from 65 to 125 code points, you have to write the following code on a pre-C++11 compiler:

#include <boost/array.hpp>

boost::array<unsigned char, 60> chars_65_125_pre11() {
    boost::array<unsigned char, 60> res;

    const unsigned char offset = 65;
    for (std::size_t i = 0; i < res.size(); ++i) {
        res[i] = i + offset;
    }

    return res;
}

Getting ready

Basic knowledge of C++ is required for this recipe along with basic knowledge of Boost.Array library.

How to do it...

The Boost.Algorithm library has all the new C++11 and C++14 algorithms. Using it, you can rewrite the previous example in the following manner:

#include <boost/algorithm/cxx11/iota.hpp>
#include <boost/array.hpp>

boost::array<unsigned char, 60> chars_65_125() {
    boost::array<unsigned char, 60> res;
    boost::algorithm::iota(res.begin(), res.end(), 65);
    return res;
}

How it works...

As you are probably aware, Boost.Algorithm has a header file for each algorithm. Just include the header file and use the required function.

There's more...

It's boring to have a library that just implements algorithms from C++ standard. That's not innovative; that's not the Boost way! That's why you can find in Boost.Algorithm, functions that are not part of C++. Here, for example, is a function that converts input into hexadecimal representation:

#include <boost/algorithm/hex.hpp>
#include <iterator>
#include <iostream>

void to_hex_test1() {
    const std::string data = "Hello word";
    boost::algorithm::hex(
        data.begin(), data.end(),
        std::ostream_iterator<char>(std::cout)
    );
}

The preceding code outputs the following:

48656C6C6F20776F7264

What's more interesting, all the functions have additional overloads that accept a range as a first parameter instead of two iterators. Range is a concept from Ranges TS. Arrays and containers that have .begin() and .end() functions satisfy the range concept. With that knowledge the previous example could be shortened:

#include <boost/algorithm/hex.hpp>
#include <iterator>
#include <iostream>

void to_hex_test2() {
    const std::string data = "Hello word";
    boost::algorithm::hex(
        data,
        std::ostream_iterator<char>(std::cout)
    );
}

C++17 will have searching algorithms from Boost.Algorithm. Boost.Algorithm library will be soon extended with new algorithms and C++20 features like constexpr usable algorithms. Keep an eye on that library, as some day, it may get an out-of-the-box solution for a problem that you're dealing with.

See also

• Official documentation for Boost.Algorithm contains a full list of functions and short descriptions for them at http://boost.org/libs/algorithm
• Experiment with new algorithms online: http://apolukhin.github.io/Boost-Cookbook