How to use async threads in C++

async_example.cpp

#include <future>

float DoWork(int idx)
{
    // Do some hard computation using idx
    // and internal read-only data structures
    // Return the float result
}

void DoAsync()
{
    // To control async threads and their results
    std::vector<std::future<float>> fut_vec;

    // Create 10 async threads
    for (int i = 0; i < 10; ++i)
        fut_vec.push_back(
                          std::async(DoWork, i));

    // Collect results from 10 async threads
    float result = 0;
    for (int i = 0; i < 10; ++i)
        result += fut_vec[i].get();
    std::cout << "Result: " << result << std::endl;
}

// Note 1: On Linux use std::launch::async launch policy
// Else threads will execute sequentially
// fut_vec.push_back(
//                   std::async(std::launch::async, DoWork, i));
//
// Note 2: To call method of a class, pass pointer to object as
// first parameter:
//
//struct DoWorkClass
//{
//    float DoWork(int idx) {}
//
//    void DoAsync()
//    {
//        // ...
//        fut_vec.push_back(
//                          std::async(std::launch::async, &DoWorkClass::DoWork, this, i);
//};