C#查找素数实现方法

using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;using System.Threading;namespace SuspendAndResume{ public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.Label label1; private System.Windows.Forms.ListBox listBox1; private System.Windows.Forms.Button button1; private System.Windows.Forms.Button button2; private System.Windows.Forms.Button button3; private System.Windows.Forms.Button button4; private System.Windows.Forms.Label label2; private System.Windows.Forms.Timer timer1; private System.ComponentModel.IContainer components; //公共委托，用于输出素数 public delegate void UD(string returnVal); //声明私有线程 private Thread pNT; //用于标识是否挂起线程 bool suspend = false; //用于标识线程时候开始运行 bool pNTstart = false; public Form1() {  InitializeComponent();  // TODO: 在 InitializeComponent 调用后添加任何构造函数代码 } protected override void Dispose( bool disposing ) {  if( disposing )  {  if (components != null)  {   components.Dispose();  }  }  base.Dispose( disposing ); } #region Windows 窗体设计器生成的代码 private void InitializeComponent() {  this.components = new System.ComponentModel.Container();  this.label1 = new System.Windows.Forms.Label();  this.listBox1 = new System.Windows.Forms.ListBox();  this.button1 = new System.Windows.Forms.Button();  this.button2 = new System.Windows.Forms.Button();  this.button3 = new System.Windows.Forms.Button();  this.button4 = new System.Windows.Forms.Button();  this.label2 = new System.Windows.Forms.Label();  this.timer1 = new System.Windows.Forms.Timer(this.components);  this.SuspendLayout();  // label1  this.label1.Location = new System.Drawing.Point(8, 8);  this.label1.Name = "label1";  this.label1.TabIndex = 0;  this.label1.Text = "已找到的素数：";  // listBox1  this.listBox1.ItemHeight = 12;  this.listBox1.Location = new System.Drawing.Point(8, 32);  this.listBox1.MultiColumn = true;  this.listBox1.Name = "listBox1";  this.listBox1.Size = new System.Drawing.Size(272, 136);  this.listBox1.TabIndex = 1;  // button1  this.button1.Location = new System.Drawing.Point(19, 184);  this.button1.Name = "button1";  this.button1.Size = new System.Drawing.Size(48, 23);  this.button1.TabIndex = 2;  this.button1.Text = "创建";  this.button1.Click += new System.EventHandler(this.button1_Click);  //  // button2  //  this.button2.Location = new System.Drawing.Point(88, 184);  this.button2.Name = "button2";  this.button2.Size = new System.Drawing.Size(48, 23);  this.button2.TabIndex = 3;  this.button2.Text = "挂起";  this.button2.Click += new System.EventHandler(this.button2_Click);  //  // button3  //  this.button3.Location = new System.Drawing.Point(157, 184);  this.button3.Name = "button3";  this.button3.Size = new System.Drawing.Size(48, 23);  this.button3.TabIndex = 4;  this.button3.Text = "恢复";  this.button3.Click += new System.EventHandler(this.button3_Click);  //  // button4  //  this.button4.Location = new System.Drawing.Point(226, 184);  this.button4.Name = "button4";  this.button4.Size = new System.Drawing.Size(48, 23);  this.button4.TabIndex = 5;  this.button4.Text = "销毁";  this.button4.Click += new System.EventHandler(this.button4_Click);  //  // label2  //  this.label2.Location = new System.Drawing.Point(24, 224);  this.label2.Name = "label2";  this.label2.Size = new System.Drawing.Size(200, 23);  this.label2.TabIndex = 6;  this.label2.Text = "线程未启动";  //  // timer1  //  this.timer1.Enabled = true;  this.timer1.Tick += new System.EventHandler(this.timer1_Tick);  //  // Form1  //  this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);  this.ClientSize = new System.Drawing.Size(292, 266);  this.Controls.Add(this.label2);  this.Controls.Add(this.button4);  this.Controls.Add(this.button3);  this.Controls.Add(this.button2);  this.Controls.Add(this.button1);  this.Controls.Add(this.listBox1);  this.Controls.Add(this.label1);  this.Name = "Form1";  this.Text = "素数";  this.Load += new System.EventHandler(this.Form1_Load);  this.ResumeLayout(false); } #endregion /// <summary> /// 应用程序的主入口点。 /// </summary> [STAThread] static void Main() {  Application.Run(new Form1()); } private void button1_Click(object sender, System.EventArgs e) {  //创建线程实例，设置属性  pNT = new Thread(new ThreadStart(GPN));  pNT.Name = "Prime Numbers Exaple";  pNT.Priority = ThreadPriority.BelowNormal;  //设置按键，停用开始按键，启用挂起按键和销毁按键  button1.Enabled = false;  button2.Enabled = true;  button4.Enabled = true;  //线程开始，并设置标识  pNT.Start();  pNTstart = true; } private void button2_Click(object sender, System.EventArgs e) {  //设置挂起bool变量为真  suspend = true;  //设置按键，停用挂起按键， 启用恢复按键  button2.Enabled = false;  button3.Enabled = true; } private void button3_Click(object sender, System.EventArgs e) {  //设置挂起bool变量为假  suspend = false;  //当线程当前状态为挂起时，恢复该线程  if(pNT.ThreadState == System.Threading.ThreadState.Suspended  || pNT.ThreadState == System.Threading.ThreadState.SuspendRequested)  {  try  {   //恢复线程   pNT.Resume();   //设置按键，停用恢复按键，启用挂起按键   button3.Enabled = false;   button2.Enabled = true;  }  catch(ThreadStateException Ex)  {   MessageBox.Show(Ex.ToString(), "提示");  }  } } private void button4_Click(object sender, System.EventArgs e) {  //设置按键，启用开始按键，停用其他按键  button1.Enabled = true;  button2.Enabled = false;  button3.Enabled = false;  button4.Enabled = false;  //销毁线程  pNT.Abort(); } //GPN为GetPrimeNumber的缩写，用于查找并显示素数 public void GPN() {  //声明变量  long Counter;  //素数个数  long NumberNow;  //当前数  long SqrtOfNow;  //辅助数，做数组下标  bool IsPrime = false; //标识是否为素数  //数组，用于存储已找到素数  long[] PrimeArray = new long[256];  //委托，用于显示素数，即将其添加到ListBox中  string[] args = new string[] {"2"};  UD UIDel = new UD(UpdateUI);  //初始化，从3开始计算，从第2个素数开始计算  NumberNow = 3;  Counter = 2;  //添加2为素数，放入素数数组并将其显示  PrimeArray[1] = 2;  this.Invoke(UIDel, args);  //循环，用于找到并输出256个素数  while(Counter <= 255)  {  IsPrime = true;  //从1到当前数的平方根，穷尽计算是否为素数  for(SqrtOfNow = 1; (PrimeArray[SqrtOfNow]   * PrimeArray[SqrtOfNow] <= NumberNow);   SqrtOfNow++)  {   //若能被已找到的素数整除，则不是素数   if(NumberNow % PrimeArray[SqrtOfNow] == 0)   {   //若不是素数，跳出for循环   IsPrime = false;   break;   }  }  //若为素数，将其添加到ListBox以显示  if(IsPrime)  {   //将素数存入数组中储存   PrimeArray[Counter] = NumberNow;   Counter++;   //将素数显示到ListBox中   args[0] = NumberNow.ToString();   this.Invoke(UIDel,args);   //利用bool变量，控制是否挂起线程   if( suspend == true)   {   //调用Suspend方法，并捕捉异常   try   {    pNT.Suspend();   }   catch(ThreadStateException Ex)   {    MessageBox.Show(Ex.ToString(), "提示");   }   }   //使线程睡眠，使过程清楚显示，且有时间挂起线程   Thread.Sleep(500);  }  //除2外，素数必为奇数，故跳过偶数的检查，优化算法  NumberNow += 2;  } } //更新ListBox的方法 void UpdateUI(string result) {  listBox1.Items.Add(result); } //利用Timer控件显示线程当前状态 private void timer1_Tick(object sender, System.EventArgs e) {  //在线程开时候再获取状态并显示  if( pNTstart )  {  label2.Text = "线程当前状态是：" + pNT.ThreadState.ToString();  } } private void Form1_Load(object sender, System.EventArgs e) {  //设置按键，启用开始按键，停用其他按键  button1.Enabled = true;  button2.Enabled = false;  button3.Enabled = false;  button4.Enabled = false; } }}