# <iterator>

**[<iterator>](https://en.cppreference.com/w/cpp/header/iterator)** provides iterator utilities: `std::advance`, `std::distance`, `std::next`, `std::prev`, iterator type traits like `std::iterator_traits`, and iterator adapters like `std::back_inserter`, `std::insert_iterator`.

Use iterator adapters to turn algorithms into list-building operations: `std::copy(..., std::back_inserter(vec))` appends to a vector.

## Example

This example uses `std::back_inserter` to copy elements into a vector, and `std::distance` and `std::next` to navigate iterators.

```cpp
// compile: g++ -std=c++11 -o iteratorexample iteratorexample.cpp
// run: ./iteratorexample
// description: iterator utilities and inserters

#include <iterator>
#include <algorithm>
#include <vector>
#include <iostream>

int main() {
    std::vector<int> src = {1, 2, 3};
    std::vector<int> dst;
    
    std::copy(src.begin(), src.end(), std::back_inserter(dst));
    
    std::cout << "distance: " << std::distance(dst.begin(), dst.end()) << "\n";
    std::cout << "next iter value: " << *std::next(dst.begin()) << "\n";
    
    return 0;
}
```