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json/docs/mkdocs/docs/examples/ordered_map.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

44 lines
1.1 KiB
C++

#include <iostream>
#include <nlohmann/json.hpp>
// simple output function
template<typename Map>
void output(const char* prefix, const Map& m)
{
std::cout << prefix << " = { ";
for (auto& element : m)
{
std::cout << element.first << ":" << element.second << ' ';
}
std::cout << "}" << '\n';
}
int main()
{
// create and fill two maps
nlohmann::ordered_map<std::string, std::string> m_ordered;
m_ordered["one"] = "eins";
m_ordered["two"] = "zwei";
m_ordered["three"] = "drei";
std::map<std::string, std::string> m_std;
m_std["one"] = "eins";
m_std["two"] = "zwei";
m_std["three"] = "drei";
// output: m_ordered is ordered by insertion order, m_std is ordered by key
output("m_ordered", m_ordered);
output("m_std", m_std);
// erase and re-add "one" key
m_ordered.erase("one");
m_ordered["one"] = "eins";
m_std.erase("one");
m_std["one"] = "eins";
// output: m_ordered shows newly added key at the end; m_std is again ordered by key
output("m_ordered", m_ordered);
output("m_std", m_std);
}