Why Are Non-Member `std::begin` and `std::end` More Than Just Container Iterators?

Non-Member Begin and End Functions in C 11: Benefits Beyond Container Iterators

The introduction of free functions std::begin and std::end in C 11 has sparked the question of their utility beyond returning iterators for standard containers. Herb Sutter's recommendation to always use these free functions prompts an investigation into their advantages.

While these functions do indeed provide a marginal benefit in terms of code conciseness for standard containers, their true value lies in addressing a fundamental limitation: non-member C-arrays do not have begin and end member functions.

This absence poses a challenge for accessing the contents of an array using range-based for loops or algorithms requiring iterators. However, the free functions std::begin and std::end solve this predicament by allowing programmers to seamlessly iterate over C-arrays. For instance, instead of using the cumbersome pointer arithmetic, one can simply write:

<code class="cpp">int arr[] = {1, 2, 3};
for (auto& element : arr | std::views::iota(0, 3)) {
    // Use element
}</code>

Additionally, the free functions offer greater flexibility in generic programming. Since they can be added to any data structure after its definition, they enable developers to extend existing libraries or create custom iterators without altering the original data structure. This is particularly beneficial when working with third-party libraries or code that cannot be modified.

In conclusion, non-member std::begin and std::end functions extend the functionality of container iterators by providing access to C-arrays and facilitating generic programming. They offer a powerful tool for writing flexible and efficient code in C .

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