using System;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        //
        static async Task Main(string[] args)
        {
            //等待执行完成
            var result = await Task.Run(() =>
            {
                Console.WriteLine("进入子线程main执行4秒");
                for (int i = 1; i <= 2; i++)
                {
                    Console.WriteLine("子线程main" +"+"+ i);
                    Thread.Sleep(2000);
                }

                Console.WriteLine("子线程main等待4秒完成返回！");
                return "子线程main返回值";
            });



            Console.WriteLine("进入主线程main方法内！");

            for (int i = 1; i <= 2; i++)
            {
                Console.WriteLine("主线程main" + "+" + i);
                Thread.Sleep(2000);
            }


            //不需要等待
            Task1();

            Task3();
            Console.WriteLine("进入主线程main方法内！");
            //等待
            await Task2();

            Console.WriteLine("进入主线程main方法内！");
            Console.WriteLine(result);
            Console.ReadLine();
        }


        private static async Task Task1()
        {
            Console.WriteLine("进入到了Task1方法内");
            var result = await Task.Run(() =>
            {
                Console.WriteLine("进入子线程task1执行5秒");
                for (int i = 1; i <= 5; i++)
                {
                    Console.WriteLine("task1"+ "+" + i);
                    Thread.Sleep(1000);
                }

                Console.WriteLine("task1子线程返回！");
                return "task1 5秒后的返回值";

            }
            );
            //主线程
            Console.WriteLine("进入task1内");
            Console.WriteLine(result);

        }

        private static async Task Task2()
        {
            Console.WriteLine("进入到了Task2方法内");
            var result = await Task.Run(() =>
            {
                Console.WriteLine("进入子线程task2执行10秒");
                for (int i = 1; i <= 10; i++)
                {
                    Console.WriteLine("task2" + "+" + i);
                    Thread.Sleep(1000);
                }

                Console.WriteLine("task2子线程返回！");
                return "task2 10秒后的返回值";

            }
            );
            Console.WriteLine("进入tast2内");
            Console.WriteLine(result);

        }


        private static async  Task Task3()
        {
            Console.WriteLine("进入到了Task3方法内");

                 for (int i = 1; i <= 10; i++)
                {
                    Console.WriteLine("task3" + "+" + i);
                    Thread.Sleep(1000);
                }
           


        }
    }
}