What are some examples of using iterators with STL vectors in C++?

Can you show me some examples of using iterators with STL vectors in C++?

Sure! Here's a simple example of using an iterator to traverse a vector in C++:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec = {1, 2, 3, 4, 5};
    for (std::vector<int>::iterator it = vec.begin(); it != vec.end(); ++it) {
        std::cout << *it << " ";
    }
    return 0;
}

This code will print the elements of the vector.

What about using a reverse iterator?

Great question! Here's how you can use a reverse iterator:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec = {1, 2, 3, 4, 5};
    for (std::vector<int>::reverse_iterator rit = vec.rbegin(); rit != vec.rend(); ++rit) {
        std::cout << *rit << " ";
    }
    return 0;
}

This will print the elements of the vector in reverse order.

Can I use a for-each loop instead?

Absolutely! You can use a range-based for loop, which is more concise:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec = {1, 2, 3, 4, 5};
    for (const auto& value : vec) {
        std::cout << value << " ";
    }
    return 0;
}

This will also print the elements of the vector.

What if I want to modify the elements while iterating?

You can modify elements using a regular iterator like this:

#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec = {1, 2, 3, 4, 5};
    for (std::vector<int>::iterator it = vec.begin(); it != vec.end(); ++it) {
        *it *= 2; // Double each element
    }
    for (const auto& value : vec) {
        std::cout << value << " ";
    }
    return 0;
}

This will double each element in the vector.