How can I use std::for_each with custom iterators in C++?

Can you explain how to use std::for_each with custom iterators in C++?

Sure! std::for_each applies a function to each element in a range defined by iterators. You can use it with custom iterators by ensuring they meet the requirements of input iterators.

What are the requirements for custom iterators to work with std::for_each?

Custom iterators need to implement certain operations like incrementing, dereferencing, and comparison. They should also be able to work with the standard algorithms.

Can you provide a code example of using std::for_each with a custom iterator?

Absolutely! Here's a simple example:

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

class CustomIterator {
    // Implementation of custom iterator
};

int main() {
    std::vector<int> vec = {1, 2, 3, 4};
    std::for_each(vec.begin(), vec.end(), [](int n) { std::cout << n << ' '; });
    return 0;
}

This applies a lambda function to each element.

What if I want to modify the elements while iterating?

You can modify elements directly in the lambda function passed to std::for_each. Just ensure your iterator allows modification.