模拟实现同步机构，以避免发生进程执行时可能出现的与时间有关的错误。
当进程并发执行时，如果对进程访问的共享变量不加限制，就会产生“与时间有关”的错误。为了防止这类错误，系统必须用同步机构来控制进程对共享变量的访问。 一般说，同步机构是由若干条同步原语所组成。本实验要求学生模拟P、V操作同步机构的实现，模拟进程的并发执行，了解进程并发执行时同步机构的作用。
模拟P、V操作实现同步机构，且用P、V操作解决生产者—消费者问题。
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; //每运行一条指令都要敲一下回车 namespace CaoZuoXiTong5 { class Program { static int[] area = new int[10]; static int empty = 10; static int full = 0; static int direction = 0;//0表示都可以，1表示只能运行producer,2表示只能运行consumer static void Main(string[] args) { int a; Console.WriteLine("随机运行Producer Consumer"); Producer producer = new Producer(); Consumer consumer = new Consumer(); while (true) { Random x = new Random(); a = x.Next(1, 3); if (direction == 1) { a = 1; } else if (direction == 2) { a = 2; } switch (a) { case 1:producer.Choose();break; case 2:consumer.Choose();break; default:break; } Console.WriteLine("---------------------\n缓冲区：{0} {1} {2} {3} {4} {5} {6} {7} {8} {9}",area[0], area[1], area[2], area[3], area[4], area[5], area[6], area[7], area[8], area[9]); Console.WriteLine("Producer:{0} Consumer:{1}",producer.Statement,consumer.Statement); Console.WriteLine("Producer断点:{0} Consumer断点:{1}",producer.Point,consumer.Point); Console.ReadLine(); } } static int P( ref int x) { int a = x; a--; if (a< 0) return 0;//不能运行，需要等待 else { x--; return 1;//可以运行 } } static void V(ref int x) { x++; } class Consumer { public int Point { get; set; } public string Statement { get; set; } public Consumer() { Point = 0; Statement = "运行"; } public void Choose() { switch (this.Point) { case 0:A(); break; case 1: B(); break; case 2: C(); break; case 3: D();break; case 4: E(); break; case 5: A(); break; default: A(); B(); C(); D(); E(); break; } } public void A() { int judge = P(ref full); Console.WriteLine("Consumer:产品P操作"); if (judge == 0) { Console.WriteLine("Consumer:Consumer因P操作进程阻塞"); this.Point = 0; this.Statement = "等待"; direction = 1; } else { this.Point = 1; this.Statement = "运行"; } } public void B() { Console.WriteLine("Consumer:取出一个产品"); for (int i = 0; i < 10; i++) { if (area[i] == 1) { area[i] = 0; break; } } this.Point = 2; } public void C() { V(ref empty); direction=0; Console.WriteLine("Consumer:缓冲区V操作"); this.Point = 3; } public void D() { Console.WriteLine("Consumer:消耗一个产品:1"); this.Point = 4; } public void E() { Console.WriteLine("Consumer:GOTO"); this.Point = 5; } } class Producer { public int Point { get; set; } public string Statement { get; set; } public Producer() { Point = 0; Statement = "运行"; } public void Choose() { switch (this.Point) { case 0: A(); break; case 1: B(); break; case 2: C(); break; case 3: D(); break; case 4: E(); break; case 5: A();break; default: A(); B(); C(); D(); E(); break; } } public void A() { Console.WriteLine("Producer:生产了一个产品:1"); this.Point = 1; } public void B() { int judge = P(ref empty); Console.WriteLine("Producer:缓冲区P操作"); if (judge == 0) { Console.WriteLine("Producer:Producer因P操作进程阻塞"); direction = 2; this.Point = 1; this.Statement = "等待"; } else this.Point = 2; this.Statement = "运行"; } public void C() { for (int i = 0; i < 10; i++) { if (area[i] == 0) { area[i] = 1; break; } } Console.WriteLine("Producer:放入一个产品"); this.Point = 3; } public void D() { V(ref full); direction=0; Console.WriteLine("Producer:产品V操作"); this.Point = 4; } public void E() { Console.WriteLine("Producer:GOTO"); this.Point = 5; } } } }才疏学浅，如有错误请多指正
