json/api/basic_json/crend/index.md

nlohmann::basic_json::crend

const_reverse_iterator crend() const noexcept;

Returns an iterator to the reverse-end; that is, one before the first element. This element acts as a placeholder, attempting to access it results in undefined behavior.

crend() points to the position before the first element, like rend(), and rbegin() to the last element. The upper row is the reversed sequence and the lower row the forward sequence; dashed arrows link each reverse iterator to the forward iterator it stores, and dashed cells are past-the-last positions.

Return value

reverse iterator to the element following the last element

Exception safety

No-throw guarantee: this member function never throws exceptions.

Complexity

Constant.

Examples

Example

The following code shows an example for crend().

#include <iostream>
#include <nlohmann/json.hpp>

using nlohmann::json;

int main()
{
    // create an array value
    json array = {1, 2, 3, 4, 5};

    // get an iterator to the reverse-end
    json::const_reverse_iterator it = array.crend();

    // increment the iterator to point to the first element
    --it;

    // serialize the element that the iterator points to
    std::cout << *it << '\n';
}

Output:

1

See also

• crbegin - returns a const reverse iterator to the last element
• rend - returns a reverse iterator to one before the first element
• cend - returns a const iterator to one past the last element
• Iterators - the article on iterators

Version history

• Added in version 1.0.0.