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Niels Lohmann
172eba6e46
Add See also links in both directions between the concept pages (features, home, integration) and the API pages, write API links in code font, give every entry a comment after a dash, and show the callback event figure on the parser callbacks page. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
1.5 KiB
1.5 KiB
nlohmann::basic_json::back
reference back();
const_reference back() const;
Returns a reference to the last element in the container. For a JSON container c, the expression c.back() is
equivalent to
auto tmp = c.end();
--tmp;
return *tmp;
Return value
In the case of a structured type (array or object), a reference to the last element is returned. In the case of number, string, boolean, or binary values, a reference to the value is returned.
Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
Exceptions
If the JSON value is #!json null, exception
invalid_iterator.214 is thrown.
Complexity
Constant.
Notes
!!! info "Precondition"
The array or object must not be empty. Calling `back` on an empty array or object yields undefined behavior.
Examples
??? example
The following code shows an example for `back()`.
```cpp
--8<-- "examples/back.cpp"
```
Output:
```json
--8<-- "examples/back.output"
```
See also
front- to access the first elementbasic_json_view::back- the same access on a zero-copy view- Element Access - overview of all ways to access elements
Version history
- Added in version 1.0.0.
- Binary values are supported since version 3.8.0.