C++ 11多线程编程：2个线程轮流输出 字母和数字。

#include 
#include 
#include 
#include 
#include 

bool readyPrintNumbers = false;
bool readyPrintLetters = false;
std::mutex m;
std::condition_variable cv;
int index = 0;


void printNumblers()
{
    for (int i = 0; i < 26; i++)
    {
        std::unique_lock lk(m);
        cv.wait(lk, [] {return readyPrintNumbers; });
        std::cout << i + 1 << " ";
        readyPrintNumbers = false;
        readyPrintLetters = true;
        cv.notify_one();// 通知 已经准备好 【打印字母】
    }
}
void printLetters()
{
    for (int i = 0; i < 26; i++)
    {
        std::unique_lock lk(m);
        cv.wait(lk, [] {return readyPrintLetters; });
        std::cout << (char)(i + 'A');

        readyPrintNumbers = true;
        readyPrintLetters = false;
        cv.notify_one();// 通知 已经准备好 【打印数字】
    }
}

int main()
{
    std::thread t1(printNumblers), t2(printLetters);//首先创建两个线程和两个函数。

    std::cout << "start main()n";//main函数开始
    
    
    readyPrintNumbers = true;
    cv.notify_one();// 通知 已经准备好 【打印数字】


    t1.join();
    t2.join();


    std::cout << "n end main()n";


    return 0;
}

二、使用atomic方式

#include 
#include 
#include 
#include 
#include 
#include 

using std::cout; using std::endl;


std::mutex m;
std::atomic readyPrintNumbers(false);
std::atomic readyPrintLetters(false);


void printNumbers()
{
    for (int i = 0; i < 26; i++)
    {
        while (!readyPrintNumbers.load())
        {
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
        }

        cout << i + 1 << " ";
        readyPrintNumbers.store(false);
        readyPrintLetters.store(true);
    }

}


void printLetters()
{
    for (int i = 0; i < 26; i++)
    {
        while (!readyPrintLetters.load())
        {
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
        }

        cout << (char)('A' + i);
        readyPrintNumbers.store(true);
        readyPrintLetters.store(false);
    }
}

int main()
{
    std::thread t1(printNumbers), t2(printLetters);//首先创建两个线程和两个函数。

    std::cout << "start main()n";//main函数开始

    readyPrintNumbers.store(true);
    t1.join();
    t2.join();


    std::cout << "n end main()n";


    return 0;
}