#include <iostream>
#include <future>
#include <chrono>
#include <condition_variable>
#include <iostream>
#include <mutex>
#include <string>
#include <thread>

using namespace std ;

int globalResult = 0 ;

int calculate_value()
{
    cout << "Calculating value in background...\n";
    this_thread::sleep_for(chrono::seconds(20)); // Simulate long computation
    globalResult = 42 ;
    return 42;
}

int main()
{
    future<int> future_result = async(launch::async, calculate_value);
    cout << "Main thread continues to execute...\n";
    cout << "Waiting for result...\n";
    int result = future_result.get(); // Blocks until the result is available
    cout << "Result is: " << result << endl;

    thread th1( calculate_value ) ;
    th1.join() ;
    cout << "Result is: " << globalResult << endl;


    return 0;
}