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### jsoncons::staj_object_iterator
```cpp
#include <jsoncons/staj_iterator.hpp>
template<
typename Key,
typename T,
typename CharT=char
> class staj_object_iterator
```
A `staj_object_iterator` is an [InputIterator](https://en.cppreference.com/w/cpp/named_req/InputIterator) that
accesses the individual stream events from a [staj_cursor](staj_cursor.md) and, provided that when it is constructed
the current stream event has type `begin_object`, it returns the elements
of the JSON object as items of type `std::pair<string_type,T>`. If when it is constructed the current stream event
does not have type `begin_object`, it becomes equal to the default-constructed iterator.
#### Member types
Member type |Definition
------------------------------------|------------------------------
`char_type`|`CharT`
`key_type`|`Key`
`value_type`|`std::pair<Key,T>`
`difference_type`|`std::ptrdiff_t`
`pointer`|`value_type*`
`reference`|`value_type&`
`iterator_category`|[std::input_iterator_tag](https://en.cppreference.com/w/cpp/iterator/iterator_tags)
#### Constructors
staj_object_iterator() noexcept; (1)
staj_object_iterator(basic_staj_cursor<char_type>& cursor); (2)
staj_object_iterator(basic_staj_cursor<char_type>& cursor,
std::error_code& ec); (3)
staj_object_iterator(const staj_object_iterator& iter); (4)
(1) Constructs the end iterator
(2) Constructs a `staj_object_iterator` that refers to the first member of the object
following the current stream event `begin_object`. If there is no such member,
returns the end iterator. If a parsing error is encountered, throws a
[ser_error](ser_error.md).
(3) Constructs a `staj_object_iterator` that refers to the first member of the object
following the current stream event `begin_object`. If there is no such member,
returns the end iterator. If a parsing error is encountered, returns the end iterator
and sets `ec`.
(4) Copy constructor
#### Member functions
const key_value_type& operator*() const
const key_value_type* operator->() const
staj_object_iterator& operator++();
staj_object_iterator operator++(int);
staj_object_iterator& increment(std::error_code& ec);
Advances the iterator to the next object member.
#### Non-member functions
template <typename Key, typename T, typename CharT>
staj_object_iterator<Key, T, CharT> begin(staj_object_iterator<Key, T, CharT> iter); (1)
template <typename T, typename CharT>
staj_object_iterator<Key, T, CharT> end(staj_object_iterator<Key, T, CharT>) noexcept; (2)
template <typename Key,typename T,typename CharT>
bool operator==(const staj_object_iterator<Key, T, CharT>& a,
const staj_object_iterator<Key, T, CharT>& b) (3)
template <typename Key,typename T,typename CharT>
bool operator!=(const staj_object_iterator<Key, T, CharT>& a, (4)
const staj_object_iterator<Key, T, CharT>& b)
(1)-(2) For range-based for loop support.
(3)-(4) As required by LegacyInputIterator
### Examples
#### Iterate over a JSON object, returning key-json value pairs
```cpp
const std::string example = R"(
{
"application": "hiking",
"reputons": [
{
"rater": "HikingAsylum.array_example.com",
"assertion": "advanced",
"rated": "Marilyn C",
"rating": 0.90
}
]
}
)";
int main()
{
json_string_cursor cursor(example);
auto iter = staj_object_iterator<std::string,json>(cursor);
for (const auto& kv : iter)
{
std::cout << kv.first << ":\n" << pretty_print(kv.second) << "\n";
}
std::cout << "\n\n";
}
```
Output:
```
application:
"hiking"
reputons:
[
{
"assertion": "advanced",
"rated": "Marilyn C",
"rater": "HikingAsylum.array_example.com",
"rating": 0.90
}
]
```
|
