std::thread的使用

1 添加头文件#include <thread>

2 使用全局函数作为线程函数

#include <iostream>
#include <thread>
#include <string>
using namespace  std;

void ThreadFunc1()
{
    std::cout << "ThreadFunc1" << std::endl;
}

void ThreadFunc2(int data)
{
    std::cout << "ThreadFunc2"<<" "<<data << std::endl;
}

void ThreadFunc3(int data1,int data2,string str)
{
    std::cout << "ThreadFunc3" << " "<< data1 << " "<< data2 << " "<< str << std::endl;
}

int main()
{
    thread th1(ThreadFunc1);
    th1.join();
    int data1 = 10;
    thread th2(ThreadFunc2,data1);
    th2.join();
    int data2 = 100;
    string str = "StrTest";
    thread th3(ThreadFunc3, data1,data2,str);
    th3.join();
    return 0;
}

3 使用类成员函数作为线程函数

#include <iostream>
#include <thread>
#include <string>
using namespace  std;


class Foo
{
public:
    void ThreadFunc1() {
        std::cout << "ThreadFunc1" << std::endl;
    }

    void ThreadFunc2(int data1,int data2) {
        std::cout << "ThreadFunc2" << " " << data1 << " " << data2 << std::endl;
    }
};

int main()
{
    Foo foo;
    thread th1(&Foo::ThreadFunc1,foo);
    th1.join();
    int data1 = 10,data2 = 100;
     thread th2(&Foo::ThreadFunc2, foo,data1,data2);
     th2.join();
    return 0;
}

4 使用lambda表达式作为线程函数

int main()
{
    thread th([] {while (1)
    {
        std::cout << "lambda" << endl;
    }
    });
    while (1)
    {
        std::cout << "main" << endl;
    }
    th.join();
    return 0;
}

结果如下：

 5 leetcode练习

题目描述：

public class Foo {
  public void one() { print("one"); }
  public void two() { print("two"); }
  public void three() { print("three"); }
}

三个不同的线程将会共用一个 Foo 实例。

线程 A 将会调用 one() 方法
线程 B 将会调用 two() 方法
线程 C 将会调用 three() 方法
请设计修改程序，以确保 two() 方法在 one() 方法之后被执行，three() 方法在 two() 方法之后被执行。

class Foo {
public:
    Foo() {
        
    }

    void first(function<void()> printFirst) {
        
        // printFirst() outputs "first". Do not change or remove this line.
     std::lock_guard<std::mutex> lock(mx_);
      printFirst();
      number_ = 1;
    }

    void second(function<void()> printSecond) {
        
        // printSecond() outputs "second". Do not change or remove this line.
        while (1)
      {
          if (number_ == 1)
          {
              std::lock_guard<std::mutex> lock(mx_);
              printSecond();
              number_ = 2;
              break;
          }
      }
    }

    void third(function<void()> printThird) {
        
        // printThird() outputs "third". Do not change or remove this line.
       while (1)
      {
          if (number_ == 2)
          {
             std::lock_guard<std::mutex> lock(mx_);
              printThird();
              number_ = 3;
              break;
          }
         
      }
    }
    
    std::mutex mx_;
    int number_ = 0;
};

class Foo
{
public:
    Foo(){}

    void first(function<void()> printFirst)
    {
        // printFirst() outputs "first". Do not change or remove this line.
        mx_.lock();
        printFirst();
        number_ = 1;
        mx_.unlock();
    }

    void second(function<void()> printSecond)
    {
        // printSecond() outputs "second". Do not change or remove this line.
        while (1)
        {
            if (number_ == 1)
            {
                mx_.lock();
                printSecond();
                number_ = 2;
                mx_.unlock();
                break;
            }
        }
    }

    void third(function<void()> printThird) 
    {
        // printThird() outputs "third". Do not change or remove this line.
        while (1)
        {
            if (number_ == 2)
            {
                mx_.lock();
                printThird();
                number_ = 3;
                mx_.unlock();
                break;

            }

        }
    }

    std::mutex mx_;
    int number_ = 0;
};

class Foo
{//三个线程分别有各自的函数，可以不用加锁
public:
    Foo() {}

    void first(function<void()> printFirst)
    {
        // printFirst() outputs "first". Do not change or remove this line.
        printFirst();
        number_ = 1;
    }

    void second(function<void()> printSecond)
    {
        // printSecond() outputs "second". Do not change or remove this line.
        while (1)
        {
            if (number_ == 1)
            {
                printSecond();
                number_ = 2;
                break;
            }
        }
    }

    void third(function<void()> printThird)
    {
        // printThird() outputs "third". Do not change or remove this line.
        while (1)
        {
            if (number_ == 2)
            {
                printThird();
                number_ = 3;
                break;

            }

        }
    }

    int number_ = 0;
};