C++多线程的基本使用

在这里编写一个程序，后台线程不断更新天气温度信息，并打印：

#include <thread>
#include <map>
#include <chrono>

using namespace std::chrono_literals;

void RefreshForecase(std::map<std::string, int> forecaseMap) {
   while (true) {
      for (auto &i : forecaseMap) { // go through the map and update the temperature
         i.second++;
         printf("%s: %d\n", i.first, i.second);
      }
      std::this_thread::sleep_for(2000ms); // milisecond in chrono_literals
   }
}

int main()
{
   std::map<std::string, int> forecastMap = {
      {"shanghai", 25},
      {"wuhan", 15},
      {"xian", 18}
   };

   std::thread bgWorker(RefreshForecase, forecastMap);

   while (true); // keep runing or the bgWorker will abort when get out of main() scope

   return 0;
}