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Showing content from https://en.cppreference.com/w/cpp/language/../ranges/cbegin.html below:

std::ranges::cbegin - cppreference.com

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)

Returns an iterator to the first element of the const-qualified argument.

(until C++23)

Returns a constant iterator to the first element of the argument.

(since C++23)

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 <cassert>
#include <ranges>
#include <vector>
 
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]

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