JSON for Modern C++  2.0.3

§ operator== [1/3]

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>
bool operator== ( const_reference  lhs,
const_reference  rhs 
)
friend

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
Linear.
Example
The example demonstrates comparing several JSON types.
1 #include <json.hpp>
2 
3 using json = nlohmann::json;
4 
5 int 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 }
basic_json<> json
default JSON class
Definition: json.hpp:10122
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 5454 of file json.hpp.