this code doesnt behave as it does in the video https://www.youtube.com/watch?v=4Udi9iAyVBQ.

threads.cpp

/*
Compiled with 
g++ -std=c++11 threads.cpp -pthreads

on ubuntu 15.04 with g++ 4.8
My strange output is:

> ./a.out 
Hello from main!
Hello from thread 25615440
Hello from thread 25615448
Hello from thread 25615456
Hello from thread 25615464
Hello from thread 25615472
Hello from thread 25615480
Hello from thread 25615488
Hello from thread 25615496
Hello from thread 25615504
Hello from thread 25615512
Hello from thread 25615520
Hello from thread 25615528
Hello from thread 25615536
Hello from thread 25615544
Hello from thread 25615552
Hello from thread 25615560
*/

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

int main(){
    std::vector<std::thread> threads;
    for (int i = 0; i < 16; ++i){
        threads.emplace_back([&]{
            //std::this_thread::sleep_for(std::chrono::milliseconds(10 * i));
            std::cout << "Hello from thread " << i << std::endl;
    
        });
    
    }   
    std::cout << "Hello from main!\n";
    for (auto & t : threads){
        t.join();
    }   

}