#include <bits/stdc++.h>
#include <thread>
using namespace std;
 
void task() {
    std::cout << "task 1 says Hi\n";
}
void task2() {
    std::cout << "task 2 says Hi\n";
}
void task3() {
    std::cout << "task 3 says Hi\n";
}
void task4() {
    std::cout << "task 4 says Hi\n";
}
int main() {
    std::thread t1(task);
    std::thread t2(task2);
    std::thread t3(task3);
    std::thread t4(task4);
 
    t4.join();
    std::cout << "main says Hi 1\n";
    // synchronize - IMPORTANT!
    t2.join();
    t3.join();
    t1.join();
    std::cout << "main says Hi 2" << std::endl;
    system("pause");
}

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