常问的算法和线程题
两个线程交替打印，也就是用两个信号量或者条件变量，打印完自己的解锁，让其他线程打印
代码语言：javascript复制#include <thread>
#include <iostream>
#include <mutex>
#include <condition_variable>
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<std::mutex> lck(data_mutex) ;
data_var.wait(lck,[]{return flag;});
std::cout<<"thread: "<< std::this_thread::get_id() << " printf: " << "A" <<std::endl;
flag = false;
data_var.notify_one();
}
}
void printB()
{
while(1)
{
std::unique_lock<std::mutex> lck(data_mutex) ;
data_var.wait(lck,[]{return !flag;});
std::cout<<"thread: "<< std::this_thread::get_id() << " printf: " << "B" <<std::endl;
flag = true;
data_var.notify_one();
}
}
int main()
{
std::thread tA(printA);
std::thread tB(printB);
tA.join();
tB.join();
return 0;
}
