std::make_reverse_iterator(3)

✨ std::make_reverse_iterator ✨

okay so bestie, welcome to the C++ Standard Library manual page for std::make_reverse_iterator — yes, that's the whole NAME section, it's literally just std::make_reverse_iterator twice, iconic minimalism honestly 💅

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🎀 Synopsis 🎀

Defined in header <iterator>
template< class Iter >                                    (since C++14)
std::reverse_iterator<Iter> make_reverse_iterator( Iter i );
                                              (constexpr since C++17)

So like. make_reverse_iterator is a convenience function template that constructs a std::reverse_iterator for the iterator i you hand it — and i must be a LegacyBidirectionalIterator, no exceptions, that's the vibe check it has to pass — with the type deduced from the type of the argument. Deduction queen behavior fr fr 🫶

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🌸 Parameters 🌸

• i — the iterator being converted into a reverse iterator. that's it. that's the whole parameter list. she's low maintenance 💖

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🦋 Return value 🦋

A std::reverse_iterator constructed from i. slay, that's the whole deal ✨

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⭐ Notes ⭐

there's a feature-test macro you can check, and here's the tea:

• Feature-test macro: __cpp_lib_make_reverse_iterator
• Value: 201402L (C++14)
• Feature: std::make_reverse_iterator

ngl knowing this macro exists is such main character energy 👑

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💜 Possible implementation 💜

like, this is what it could look like under the hood, and it's giving "so simple it's almost rude":

template<class Iter>
constexpr std::reverse_iterator<Iter> make_reverse_iterator(Iter i)
{
    return std::reverse_iterator<Iter>(i);
}

one-line body. one singular return. ate and left no crumbs 🔥

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🌈 Example 🌈

// Run this code — go on, run it, I'll wait 🧚

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

int main()
{
    std::vector<int> v{1, 3, 10, 8, 22};

    std::sort(v.begin(), v.end());
    std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, ", "));
    std::cout << '\n';

    std::copy(std::make_reverse_iterator(v.end()),
              std::make_reverse_iterator(v.begin()),
              std::ostream_iterator<int>(std::cout, ", "));
    std::cout << '\n';
}

🍓 Output 🍓

1, 3, 8, 10, 22,
22, 10, 8, 3, 1,

notice how we're passing v.end() first and v.begin() second? that's the reverse-iterator moment bestie, that's the whole personality 😭💀

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👑 See also 👑

• reverse_iterator — iterator adaptor for reverse-order traversal (class template)
• rbegin — returns a reverse iterator to the beginning of a container or array (function template) (C++14)
• crbegin — (function template) (C++14)
• rend — returns a reverse end iterator for a container or array (function template) (C++14)
• crend — (function template) (C++14)

heads up bestie: the c-prefixed ones (crbegin, crend) show up as plain (function template) (C++14) in the original page, so that's exactly how I'm giving them to you — no invented descriptions, no cap 🙈

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