C++ 11 三个线程打印ABC（顺序打印）

#include <iostream>
#include <thread>
#include <condition_variable>
#include <vector>
#include <algorithm>

std::mutex mtx;
std::condition_variable cvar;
char g_ch = 0;

void print_fun(char ch)
{
int cyle_cnt = 10;
char ch_ = ch - 'A';

for (int i = 0; i < cyle_cnt; i++)
{
std::unique_lock<std::mutex>ulk(mtx);
cvar.wait(ulk, [ch_] {return ch_ == g_ch; });
std::cout << (char)(ch_ + 'A');
g_ch = (ch_ + 1) % 3;
ulk.unlock();

cvar.notify_all();
}
}

int main()
{
std::vector<std::thread> threads;
threads.push_back(std::thread(print_fun, 'A'));
threads.push_back(std::thread(print_fun, 'B'));
threads.push_back(std::thread(print_fun, 'C'));

std::for_each(threads.begin(), threads.end(), std::mem_fn(&std::thread::join));

std::cout << std::endl;

system("pause");

return 0;
}