JSON for Modern C++ 3.0

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basic_json
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basic_json
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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>
void nlohmann::basic_json::clear | ( |  | ) |
| inlinenoexcept
Clears the content of a JSON value and resets it to the default value as if basic_json(value_t) would have been called:
Value type | initial value
--- | ---
null | `null`
boolean | `false`
string | `""`
number | `0`
object | `{}`
array | `[]`
  Note Floating-point numbers are set to `0.0` which will be serialized to `0`. The vale type remains number_float_t. Complexity Linear in the size of the JSON value. Example The example below shows the effect of clear to different JSON types. 1 #include <json.hpp> 2 3 using namespace nlohmann; 4 5 int main() 6 { 7 // create JSON values 8 json j_null; 9 json j_boolean = true; 10 json j_number_integer = 17; 11 json j_number_float = 23.42; 12 json j_object = {{"one", 1}, {"two", 2}}; 13 json j_array = {1, 2, 4, 8, 16}; 14 json j_string = "Hello, world"; 15 16 // call clear() 17 j_null.clear(); 18 j_boolean.clear(); 19 j_number_integer.clear(); 20 j_number_float.clear(); 21 j_object.clear(); 22 j_array.clear(); 23 j_string.clear(); 24 25 // serialize the cleared values() 26 std::cout << j_null << '\n'; 27 std::cout << j_boolean << '\n'; 28 std::cout << j_number_integer << '\n'; 29 std::cout << j_number_float << '\n'; 30 std::cout << j_object << '\n'; 31 std::cout << j_array << '\n'; 32 std::cout << j_string << '\n'; 33 } nlohmann::basic_json::clear void clear() noexcept clears the contents Definition: json.hpp:3082 nlohmann::basic_json a class to store JSON values Definition: json.hpp:121 nlohmann namespace for Niels Lohmann Definition: json.hpp:56 Output:
      null
      false
      0
      0
      {}
      []
      ""
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/clear.cpp -o clear
.