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~basic_json
| 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 = int64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator>
const_reference nlohmann::basic_json::at | ( | size_type | idx | ) | const
| inline
  Returns a const reference to the element at specified location idx, with bounds checking. Parameters
  [in] | idx | index of the element to access
  Returns const reference to the element at index idx Exceptions
  std::domain_error | if JSON is not an array
  std::out_of_range | if the index idx is out of range of the array; that is, `idx >= size()`
  Complexity Constant. Example The example below shows how array elements can be read using at. 1 #include <json.hpp> 2 3 using namespace nlohmann; 4 5 int main() 6 { 7 // create JSON array 8 json array = {"first", "2nd", "third", "fourth"}; 9 10 // output element at index 2 (third element) 11 std::cout << array.at(2) << '\n'; 12 13 // try to read beyond the array limit 14 try 15 { 16 std::cout << array.at(5) << '\n'; 17 } 18 catch (std::out_of_range) 19 { 20 std::cout << "out of range" << '\n'; 21 } 22 } nlohmann::basic_json a class to store JSON values Definition: json.hpp:121 nlohmann::basic_json::at reference at(size_type idx) access specified array element with bounds checking Definition: json.hpp:2079 nlohmann namespace for Niels Lohmann Definition: json.hpp:56 Output:
      "third"
      out of range
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/at__size_type_const.cpp -o at__size_type_const
.