C++多线程编程-循环输出

三个线程有序循环输出ABC

#include <bits/stdc++.h>
#include <thread>
#include <condition_variable>

using namespace std;

mutex mtx;
condition_variable cvar;
int g_ch = 0;

void print_fun(char ch) {

    int cid = ch-'A';
    for (int i = 0; i < 5; i++) {
        unique_lock<mutex> ulk(mtx);

        cvar.wait(ulk, [cid] {
			return cid == g_ch;
		});

        cout << (char)(cid + 'A') <<endl;

        g_ch = (cid + 1) % 3;

        ulk.unlock();
        cvar.notify_all();
    }
}

int main() {

    vector<thread> threads;
    threads.push_back(thread(print_fun, 'A'));
    threads.push_back(thread(print_fun, 'B'));
    threads.push_back(thread(print_fun, 'C'));

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

    return 0;
}