Passing functions to methods

#include <iostream>
#include <thread>
#include <chrono>

struct Timer {
    std::function<void()> handler_;
    std::atomic<bool> is_running_;

    explicit Timer(std::function<void()> handler) :
            handler_(std::move(handler)), is_running_(false) {}

    void run_timer(int interval_in_seconds) {
        is_running_ = true;
        while (is_running_) {
            handler_();
            std::this_thread::sleep_for(std::chrono::seconds(interval_in_seconds));
        }
    }

    void stop_timer() {
        is_running_ = false;
    }
};

int main() {
    std::atomic<int> counter(0);

    Timer counter_timer([&] {
        // get current counter and increase on 1
        std::cout << "tick: " << counter.fetch_add(1) << "\n";
    });

    std::thread t = std::thread([&] {
        std::this_thread::sleep_for(std::chrono::seconds(10));
        counter_timer.stop_timer();
    });

    std::cout << "Run timer for 10 seconds\n";
    // blocking call until stop_timer is called
    counter_timer.run_timer(1);
    std::cout << "Timer finished\n";

    t.join();
}