::cbegin - cppreference.com (original) (raw)

constexpr iterator begin() const noexcept;	(1)	(since C++20)
constexpr const_iterator cbegin() const noexcept;	(2)	(since C++23)

Returns an iterator to the first element of *this.

If *this is empty, the returned iterator will be equal to end().

[edit] Return value

Iterator to the first element.

[edit] Complexity

Constant.

[edit] Example

#include #include void print(std::span array) { std::cout << "array = "; for (auto it = array.begin(); it != array.end(); ++it) std::cout << *it << ' '; std::cout << '\n'; } void set_first_element(std::span sp, int new_value) { if (!sp.empty()) { std::cout << "old *begin = " << *sp.begin() << '\n'; *sp.begin() = new_value; std::cout << "new *begin = " << *sp.begin() << '\n'; } } int main() { int array[]{1, 3, 4, 5}; print(array); set_first_element(array, 2); print(array); }

Output:

array = 1 3 4 5 old *begin = 1 new *begin = 2 array = 2 3 4 5

[edit] See also

| | returns an iterator to the end (public member function) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns an iterator to the beginning of a container or array (function template) [edit] |