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2f087c6b73
- API pages for operator[], at, front, back, find, contains, count, begin, end, cbegin, cend, items, and type_name of basic_json_view, linked both ways with the basic_json pages - the feature page and size() describe document order and duplicate keys - the examples show when the view helps: reading a few fields of a large text, probing optional members, and members in source order Signed-off-by: Niels Lohmann <mail@nlohmann.me>
1.3 KiB
1.3 KiB
nlohmann::basic_json_view::cbegin
iterator cbegin() const noexcept;
Returns an iterator to the first element, in document order. Equivalent to begin(): a view
is always read-only, so #!cpp const_iterator and #!cpp iterator are the same type, and cbegin() exists only so
that generic code that expects a cbegin()/cend() pair works with a view too.
Return value
Iterator to the first element; identical to what begin() returns.
Exception safety
No-throw guarantee: this function never throws exceptions.
Complexity
Constant.
Examples
??? example
The example below sums many measurements with `std::accumulate`, using `cbegin()`/[`cend()`](cend.md) as the
range -- the same way it would for any standard container -- without ever materializing the whole array into a
`BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__cbegin.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__cbegin.output"
```
See also
- begin - returns an iterator to the first element
- cend - returns a const iterator to one past the last element
BasicJsonType::cbegin- the corresponding function ofbasic_json
Version history
- Added in version 3.13.0.