//OPT: -lpthread
#include<thread>
#include<sstream>
#include<iostream>
#include<vector>
#include<atomic>
#include<future>


using namespace std;

void print100(int threadnum) {
	for(int i=0;i<100;i++)
		cout << "thread " << threadnum << ", line " << i << endl;
}

void print100plus(int threadnum, int &x) {
	for(int i=0;i<100;i++)
		cout << "thread " << threadnum << " (" << this_thread::get_id() << ") " << ", line " << i << endl;
	x++;
}

// very bad way to compute this!
int computesum(int start, int end) {
	int ans = 0;
	for(int i=start;i<end;i++)
		ans += i;
	return ans;
}

int main(int argc, char **argv) {
	async(launch::async,print100,1);
	async(launch::async,print100,2);

	auto a1 = async(launch::async,computesum,0,10000);
	auto a2 = async(launch::async,computesum,10000,20000);
	auto a3 = async(launch::async,computesum,20000,30000);

	cout << a1.get() + a2.get() + a3.get() << endl;
}