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

| Defined in header | | | | ------------------------------------------------------------------------------------------------------------ | | ------------------------------------------ | | Defined in header | | | | inline namespace /* unspecified */ { inline constexpr /* unspecified */ cbegin = /* unspecified */; } | | (since C++20) (customization point object) | | Call signature | | | | template< class T > requires /* see below */ constexpr /* see below */ auto cbegin( T&& t ); | | (since C++20) |

The return type models std::input_or_output_iterator and constant-iterator(since C++23) in all cases.

Customization point objects

The name ranges::cbegin denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.

[edit] Notes

For an lvalue range e of type T, ranges::cbegin(e) is equivalent to

[edit] Example

#include #include #include   int main() { std::vector v{3, 1, 4}; auto vi = std::ranges::cbegin(v); assert(3 == *vi); ++vi; // OK, constant-iterator object is mutable assert(1 == *vi); // *vi = 13; // Error: constant-iterator points to an immutable element   int a[]{3, 1, 4}; auto ai = std::ranges::cbegin(a); // cbegin works with C-arrays as well assert(3 == *ai and *(ai + 1) == 1); // *ai = 13; // Error: read-only variable is not assignable }

[edit] See also

| | returns an iterator to the beginning of a range(customization point object)[edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns an iterator to the beginning of a container or array (function template) [edit] |