fork download
copy 
  1. // future::wait_for
  2. #include <iostream>       // std::cout
  3. #include <future>         // std::async, std::future
  4. #include <chrono>         // std::chrono::milliseconds
  5.  
  6. // a non-optimized way of checking for prime numbers:
  7. bool is_prime (int x) {
  8.   for (int i=2; i<x; ++i) if (x%i==0) return false;
  9.   return true;
  10. }
  11.  
  12. int main ()
  13. {
  14.   // call function asynchronously:
  15.   std::future<bool> fut = std::async (is_prime,700020007); 
  16.  
  17.   // do something while waiting for function to set future:
  18.   std::cout << "checking, please wait";
  19.   std::chrono::milliseconds span (0);
  20.   while (fut.wait_for(span)==std::future_status::timeout)
  21.     std::cout << '.';
  22.  
  23.   bool x = fut.get();
  24.  
  25.   std::cout << "\n700020007 " << (x?"is":"is not") << " prime.\n";
  26.  
  27.   return 0;
  28. }
Success #stdin #stdout 1.68s 4568KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
checking, please wait..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
700020007 is prime.
https://ideone.com/Ex4st2
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!