JSON for Modern C++  2.0.0
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>
constexpr value_t nlohmann::basic_json::type ( ) const
inlinenoexcept

Return the type of the JSON value as a value from the value_t enumeration.

Returns
the type of the JSON value
Complexity
Constant.
Exception safety
No-throw guarantee: this member function never throws exceptions.
Example
The following code exemplifies type() for all JSON types.
1 #include <json.hpp>
2 
3 using json = nlohmann::json;
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 type()
17  std::cout << std::boolalpha;
18  std::cout << (j_null.type() == json::value_t::null) << '\n';
19  std::cout << (j_boolean.type() == json::value_t::boolean) << '\n';
20  std::cout << (j_number_integer.type() == json::value_t::number_integer) << '\n';
21  std::cout << (j_number_float.type() == json::value_t::number_float) << '\n';
22  std::cout << (j_object.type() == json::value_t::object) << '\n';
23  std::cout << (j_array.type() == json::value_t::array) << '\n';
24  std::cout << (j_string.type() == json::value_t::string) << '\n';
25 }
basic_json<> json
default JSON class
Definition: json.hpp:9587
object (unordered set of name/value pairs)
array (ordered collection of values)
number value (floating-point)
Output (play with this example online):
true
true
true
true
true
true
true
The example code above can be translated with
g++ -std=c++11 -Isrc doc/examples/type.cpp -o type 
Since
version 1.0.0

Definition at line 2133 of file json.hpp.