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58 lines
1.3 KiB
Markdown
58 lines
1.3 KiB
Markdown
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# basic_json::size
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```cpp
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size_type size() const noexcept;
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```
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Returns the number of elements in a JSON value.
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## Return value
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The return value depends on the different types and is defined as follows:
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Value type | return value
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----------- | -------------
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null | `0`
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boolean | `1`
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string | `1`
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number | `1`
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binary | `1`
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object | result of function object_t::size()
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array | result of function array_t::size()
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## Exception safety
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No-throw guarantee: this function never throws exceptions.
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## Complexity
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Constant, as long as [`array_t`](array_t.md) and [`object_t`](object_t.md) satisfy the
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[Container](https://en.cppreference.com/w/cpp/named_req/Container) concept; that is, their `size()` functions have
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constant complexity.
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## Notes
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This function does not return the length of a string stored as JSON value -- it returns the number of elements in the
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JSON value which is `1` in the case of a string.
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## Example
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??? example
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The following code calls `size()` on the different value types.
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```cpp
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--8<-- "examples/size.cpp"
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```
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Output:
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```json
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--8<-- "examples/size.output"
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```
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## Version history
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- Added in version 1.0.0.
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- Extended to return `1` for binary types in version 3.8.0.
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