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json/docs/mkdocs/docs/examples/operator__value_t.cpp
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Niels Lohmann 330fbead59 Document clang-tidy exclusions, drop unneeded ones, and clean up doc examples (#5909)
* Document clang-tidy exclusions and drop unneeded ones

Re-enable every excluded check in a run of clang-tidy 22 over all tests
and remove the seven that never fire (cert-err58-cpp,
clang-analyzer-webkit.NoUncountedMemberChecker,
cppcoreguidelines-virtual-class-destructor, google-readability-function-size,
hicpp-function-size, hicpp-no-assembler, readability-function-size).

Document the reason for every remaining exclusion at the top of the file.

Exclude in advance the checks that only exist in clang-tidy 23 and are
noise here (bugprone-signed-bitwise, *-explicit-constructor,
readability-trailing-comma, modernize-use-string-view), plus
modernize-use-integer-sign-comparison, which needs C++20 std::cmp_less
and flags deliberate casts.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy findings in documentation examples and replace redundant aliases

Apply clang-tidy fixes to the documentation examples:
- performance-avoid-endl: std::endl -> '\n'
- readability-qualified-auto: auto -> auto* / const auto*
- performance-for-range-copy: copy -> const reference
- google-readability-casting: C-style cast -> static_cast

Replace redundant aliases (readability-redundant-qualified-alias) such as
"using json = nlohmann::json;" with "using nlohmann::json;" in the
documentation, README, examples, tests, and benchmarks. Aliases at class
scope and aliases of other types (with_base_class_t etc.) are kept.

No changes to the library or its public API. All changed examples were
compiled and run; their output matches the stored .output files (except
max_size and meta, which depend on the platform and compiler).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Format doc examples with the pinned astyle

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:07:51 +01:00

39 lines
1.3 KiB
C++

#include <iostream>
#include <nlohmann/json.hpp>
using nlohmann::json;
int main()
{
// create JSON values
json j_null;
json j_boolean = true;
json j_number_integer = -17;
json j_number_unsigned = 42u;
json j_number_float = 23.42;
json j_object = {{"one", 1}, {"two", 2}};
json j_array = {1, 2, 4, 8, 16};
json j_string = "Hello, world";
// call operator value_t()
json::value_t t_null = j_null;
json::value_t t_boolean = j_boolean;
json::value_t t_number_integer = j_number_integer;
json::value_t t_number_unsigned = j_number_unsigned;
json::value_t t_number_float = j_number_float;
json::value_t t_object = j_object;
json::value_t t_array = j_array;
json::value_t t_string = j_string;
// print types
std::cout << std::boolalpha;
std::cout << (t_null == json::value_t::null) << '\n';
std::cout << (t_boolean == json::value_t::boolean) << '\n';
std::cout << (t_number_integer == json::value_t::number_integer) << '\n';
std::cout << (t_number_unsigned == json::value_t::number_unsigned) << '\n';
std::cout << (t_number_float == json::value_t::number_float) << '\n';
std::cout << (t_object == json::value_t::object) << '\n';
std::cout << (t_array == json::value_t::array) << '\n';
std::cout << (t_string == json::value_t::string) << '\n';
}