C++11用两个线程轮流打印整数的实现方法

#include <thread>
#include <iostream>
#include <mutex>
#include <condition_variable>
 
std::mutex data_mutex;
std::condition_variable data_var;
bool label = false;
 
void printodd()
{
  std::unique_lock<std::mutex> ulock(data_mutex) ;
  for(int odd = 1; odd <= 100; odd += 2 )
  {
    data_var.wait(ulock,[]{return label;});
    std::cout<< std::this_thread::get_id() << ": " << odd <<std::endl;
    label = false;
    data_var.notify_one();
  }
}
 
void printeven()
{
  std::unique_lock<std::mutex> ulock(data_mutex) ;
  for(int even = 0; even < 100; even += 2 )
  {
    std::cout<< std::this_thread::get_id() << ": " << even <<std::endl;
    data_var.notify_one();
    label = true;
    data_var.wait(ulock,[]{return !label;});
  }
}
 
int main()
{
  std::thread t1(printeven);
  std::thread t2(printodd);
  t1.join();
  t2.join();
  std::cout<<"end!"<<std::endl;
  return 0;
}