C++笔试题之两个线程轮流（交替）打印A和B

这里使用C++11的线程语法来实现，一个线程打印A，一个线程打印B，交替进行。

#include 
#include 
#include 
#include 

std::mutex data_mutex;
std::condition_variable data_var;
bool flag = true;

void printA()
{
    while(1)
    {
        std::this_thread::sleep_for(std::chrono::seconds(1));
        std::unique_lock lck(data_mutex) ;
        data_var.wait(lck,[]{return flag;});
        std::cout<<"thread: "<< std::this_thread::get_id() << "   printf: " << "A" < lck(data_mutex) ;
        data_var.wait(lck,[]{return !flag;});
        std::cout<<"thread: "<< std::this_thread::get_id() << "   printf: " << "B" <

这个相当于始终只生产一个产品的生产者和消费者模型，关于C++11实现的生产者和消费者，详见：

https://blog.csdn.net/caoshangpa/article/details/53179154