How do I use STL iterators in C++?

Can you explain what STL iterators are in C++?

STL iterators are objects that allow you to traverse the elements of a container in C++. They provide a way to access elements without exposing the underlying structure.

How do I use an iterator to loop through a vector?

You can use a for loop with an iterator like this:

std::vector<int> vec = {1, 2, 3, 4};
for (auto it = vec.begin(); it != vec.end(); ++it) {
    std::cout << *it << ' ';
}

This will print each element in the vector.

What are the different types of iterators available in STL?

STL provides several types of iterators:

1. Input Iterator
2. Output Iterator
3. Forward Iterator
4. Bidirectional Iterator
5. Random Access Iterator. Each type has different capabilities and use cases.

Can you give an example of using a reverse iterator?

Sure! Here's how you can use a reverse iterator with a vector:

std::vector<int> vec = {1, 2, 3, 4};
for (auto rit = vec.rbegin(); rit != vec.rend(); ++rit) {
    std::cout << *rit << ' ';
}

This will print the elements in reverse order.