C++多线程创建与同步实例解析

#include <iostream>
#include <thread>

void say_hello() {
    std::cout << "Hello from thread " << std::this_thread::get_id() << std::endl;
}

int main() {
    std::thread t(say_hello);  // 启动线程
    std::cout << "Main thread running." << std::endl;
    t.join();  // 等待线程结束
    return 0;
}

#include <iostream>
#include <thread>

void print_number(int& n) {
    n += 10;
    std::cout << "Thread: n = " << n << std::endl;
}

int main() {
    int num = 5;
    std::thread t(print_number, std::ref(num));  // 使用std::ref传引用
    t.join();
    std::cout << "Main: num = " << num << std::endl;  // 输出15
    return 0;
}

#include <iostream>
#include <thread>

int main() {
    auto task = []() {
        std::cout << "Lambda thread running." << std::endl;
    };

    std::thread t(task);
    t.join();
    return 0;
}

#include <iostream>
#include <thread>
#include <mutex>

std::mutex mtx;
int shared_counter = 0;

void increment() {
    for (int i = 0; i < 100000; ++i) {
        std::lock_guard<std::mutex> lock(mtx);  // 自动加锁/解锁
        ++shared_counter;
    }
}

int main() {
    std::thread t1(increment);
    std::thread t2(increment);

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

    std::cout << "Final counter value: " << shared_counter << std::endl;
    return 0;
}