JSON for Modern C++ 2.1.1
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◆ operator== [2/3]

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>
template<typename ScalarType , typename std::enable_if< std::is_scalar< ScalarType >::value, int >::type = 0>
bool operator== ( const_reference  lhs,
const ScalarType  rhs 
)
friend

comparison: equal

Compares two JSON values for equality according to the following rules:

  • Two JSON values are equal if (1) they are from the same type and (2) their stored values are the same.
  • Integer and floating-point numbers are automatically converted before comparison. Floating-point numbers are compared indirectly: two floating-point numbers f1 and f2 are considered equal if neither f1 > f2 nor f2 > f1 holds.
  • Two JSON null values are equal.
Parameters
[in]lhsfirst JSON value to consider
[in]rhssecond JSON value to consider
Returns
whether the values lhs and rhs are equal
Complexity\n Linear.
Example\n The example demonstrates comparing several JSON
types.
1#include <json.hpp>
2
3using json = nlohmann::json;
4
5int main()
6{
7 // create several JSON values
8 json array_1 = {1, 2, 3};
9 json array_2 = {1, 2, 4};
10 json object_1 = {{"A", "a"}, {"B", "b"}};
11 json object_2 = {{"B", "b"}, {"A", "a"}};
12 json number_1 = 17;
13 json number_2 = 17.000000000000001L;
14 json string_1 = "foo";
15 json string_2 = "bar";
16
17 // output values and comparisons
18 std::cout << std::boolalpha;
19 std::cout << array_1 << " == " << array_2 << " " << (array_1 == array_2) << '\n';
20 std::cout << object_1 << " == " << object_2 << " " << (object_1 == object_2) << '\n';
21 std::cout << number_1 << " == " << number_2 << " " << (number_1 == number_2) << '\n';
22 std::cout << string_1 << " == " << string_2 << " " << (string_1 == string_2) << '\n';
23}
static basic_json array(std::initializer_list< basic_json > init=std::initializer_list< basic_json >())
explicitly create an array from an initializer list
Definition json.hpp:2165
a class to store JSON values
Definition json.hpp:1040
basic_json<> json
default JSON class
Definition json.hpp:12369

Output (play with this example online):
[1,2,3] == [1,2,4] false
{"A":"a","B":"b"} == {"A":"a","B":"b"} true
17 == 17 true
"foo" == "bar" false

The example code above can be translated with
g++ -std=c++11 -Isrc doc/examples/operator__equal.cpp -o operator__equal 
Since
version 1.0.0

Definition at line 5963 of file json.hpp.