Range access

在 Iterator library# Range access 总结了 range access interface，显然这样的设计是遵循"the interface principle"的，这样的设计能够充分发挥ADL。

cppreference Iterator library# Range access

interface	explanation
begin cbegin(C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)
end cend(C++11)(C++14)	returns an iterator to the end of a container or array (function template)
rbegin crbegin(C++14)	returns a reverse iterator to a container or array (function template)
rend crend(C++14)	returns a reverse end iterator for a container or array (function template)
size ssize(C++17)(C++20)	returns the size of a container or array (function template)
empty(C++17)	checks whether the container is empty (function template)
data(C++17)	obtains the pointer to the underlying array (function template)

Example

rosettacode Loop over multiple arrays simultaneously

#include <iostream>
#include <iterator>

int main(int argc, char *argv[])
{
    char lowers[] = { 'a', 'b', 'c' };
    char uppers[] = { 'A', 'B', 'C' };
    int nums[] = { 1, 2, 3 };

    auto ilow = std::begin(lowers);
    auto iup = std::begin(uppers);
    auto inum = std::begin(nums);

    for (; ilow != std::end(lowers) and iup != std::end(uppers) and inum != std::end(nums); ++ilow, ++iup, ++inum)
    {
        std::cout << *ilow << *iup << *inum << "\n";
    }
}

User-defined overloads and ADL

关于这一点，在cppreference std::begin, std::cbegin、cppreference std::end, std::cend中，都有描述，下面是截取自cppreference std::begin, std::cbegin：

Similar to the use of swap (described in Swappable), typical use of the begin function in generic context is an equivalent of using std::begin; begin(arg);, which allows both the ADL-selected overloads for user-defined types and the standard library function templates to appear in the same overload set.