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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>
reference nlohmann::basic_json::operator[] | ( | size_type | idx | ) |
| inline
  Returns a reference to the element at specified location idx. Note If idx is beyond the range of the array (i.e., `idx >= size()`), then the array is silently filled up with `null` values to make `idx` a valid reference to the last stored element. Parameters
  [in] | idx | index of the element to access
  Returns reference to the element at index idx Exceptions
  std::domain_error | if JSON is not an array or null
  Complexity Constant if idx is in the range of the array. Otherwise linear in `idx - size()`. Example The example below shows how array elements can be read and written using [] operator. Note the addition of `null` values. 1 #include <json.hpp> 2 3 using namespace nlohmann; 4 5 int main() 6 { 7 // create a JSON array 8 json array = {1, 2, 3, 4, 5}; 9 10 // output element at index 3 (fourth element) 11 std::cout << array[3] << '\n'; 12 13 // change last element to 6 14 array[array.size() - 1] = 6; 15 16 // output changed array 17 std::cout << array << '\n'; 18 19 // write beyond array limit 20 array[10] = 11; 21 22 // output changed array 23 std::cout << array << '\n'; 24 } nlohmann::basic_json a class to store JSON values Definition: json.hpp:121 nlohmann namespace for Niels Lohmann Definition: json.hpp:56 Output:
      4
      [1,2,3,4,6]
      [1,2,3,4,6,null,null,null,null,null,11]
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/operatorarray__size_type.cpp -o operatorarray__size_type
.