65 lines
1.5 KiB
Markdown
65 lines
1.5 KiB
Markdown
# nlohmann::basic_json::cbegin
|
|
|
|
```
|
|
const_iterator cbegin() const noexcept;
|
|
```
|
|
|
|
Returns an iterator to the first element.
|
|
|
|
`cbegin()` points to the first element, like `begin()`, and `end()` to the position after the last element; the dashed cell is the past-the-last position, which must not be dereferenced.
|
|
|
|
## Return value
|
|
|
|
iterator to the first element
|
|
|
|
## Exception safety
|
|
|
|
No-throw guarantee: this member function never throws exceptions.
|
|
|
|
## Complexity
|
|
|
|
Constant.
|
|
|
|
## Examples
|
|
|
|
Example
|
|
|
|
The following code shows an example for `cbegin()`.
|
|
|
|
```
|
|
#include <iostream>
|
|
#include <nlohmann/json.hpp>
|
|
|
|
using nlohmann::json;
|
|
|
|
int main()
|
|
{
|
|
// create an array value
|
|
const json array = {1, 2, 3, 4, 5};
|
|
|
|
// get an iterator to the first element
|
|
json::const_iterator it = array.cbegin();
|
|
|
|
// serialize the element that the iterator points to
|
|
std::cout << *it << '\n';
|
|
}
|
|
```
|
|
|
|
Output:
|
|
|
|
```
|
|
1
|
|
```
|
|
|
|
## See also
|
|
|
|
- [`begin`](https://json.nlohmann.me/api/basic_json/begin/index.md) - returns an iterator to the first element
|
|
- [`cend`](https://json.nlohmann.me/api/basic_json/cend/index.md) - returns a const iterator to one past the last element
|
|
- [`crbegin`](https://json.nlohmann.me/api/basic_json/crbegin/index.md) - returns a const reverse iterator to the last element
|
|
- [Iterators](https://json.nlohmann.me/features/iterators/index.md) - the article on iterators
|
|
- [`basic_json_view::cbegin`](https://json.nlohmann.me/api/basic_json_view/cbegin/index.md) - the same iteration on a zero-copy view
|
|
|
|
## Version history
|
|
|
|
- Added in version 1.0.0.
|