JSON for Modern C++  3.7.0

◆ crbegin()

template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
const_reverse_iterator nlohmann::basic_json::crbegin ( ) const

Returns a const iterator to the reverse-beginning; that is, the last element.

Illustration from cppreference.com
This function helps basic_json satisfying the ReversibleContainer requirements:
  • The complexity is constant.
  • Has the semantics of const_cast<const basic_json&>(*this).rbegin().
The following code shows an example for crbegin().
1 #include <iostream>
2 #include <nlohmann/json.hpp>
4 using json = nlohmann::json;
6 int main()
7 {
8  // create an array value
9  json array = {1, 2, 3, 4, 5};
11  // get an iterator to the reverse-beginning
14  // serialize the element that the iterator points to
15  std::cout << *it << '\n';
16 }
basic_json<> json
default JSON class
Definition: json.hpp:2355
json_reverse_iterator< typename basic_json::const_iterator > const_reverse_iterator
a const reverse iterator for a basic_json container
Definition: json.hpp:14689
const_reverse_iterator crbegin() const noexcept
returns a const reverse iterator to the last element
Definition: json.hpp:18715
static basic_json array(initializer_list_t init={})
explicitly create an array from an initializer list
Definition: json.hpp:15905

Output (play with this example online):
The example code above can be translated with
g++ -std=c++11 -Isingle_include doc/examples/crbegin.cpp -o crbegin 
See also
rbegin() – returns a reverse iterator to the beginning
rend() – returns a reverse iterator to the end
crend() – returns a const reverse iterator to the end
version 1.0.0

Definition at line 18715 of file json.hpp.