Wrapper for a promise and a corresponding future

PromiseFuture.cpp

#include <future>
#include <iostream>
#include <thread>

template <typename T>
class PromiseFuture {
private:
	std::promise<T> promise;
	std::future<T> future;
public:
	PromiseFuture()
	: promise(std::promise<T>()), future(promise.get_future())
	{}

	void operator=(T const & value)
	{
		promise.set_value(value);
	}

	operator T()
	{
		return future.get();
	}
};


int sum(int a, int b)
{
	return a + b;
}


int main()
{
	PromiseFuture<int> result1;
	PromiseFuture<int> result2;

	std::thread t1([&](){ result1 = sum(1, 2); });
	std::thread t2([&](){ result2 = sum(3, 4); });

	std::cout << result1 << "\n";
	std::cout << result2 << "\n";

	t1.join();
	t2.join();

	return 0;
}