C#查找素數實現方法
更新時間:2014年08月12日 11:37:28 投稿:shichen2014
這篇文章主要介紹了C#查找素數實現方法,程序中有很多使用的功能模塊,非常適合C#初學者學習借鑒,需要的朋友可以參考下
本文所述為C#查找素數的程序代碼,包括了可視化窗體的代碼,找素數的方法可以借鑒。雖然實現的功能簡單,不過為了演示一些C#技巧,本文實例中還用到了線程技術、ListBox列表框的使用、設置程序掛起等操作,其中備有詳盡的注釋,幫助大家更好的理解。
具體實現代碼如下:
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,用于輸出素數 public delegate void UD(string returnVal); //聲明私有線程 private Thread pNT; //用于標識是否掛起線程 bool suspend = false; //用于標識線程時候開始運行 bool pNTstart = false; public Form1() { InitializeComponent(); // TODO: 在 InitializeComponent 調用后添加任何構造函數代碼 } protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); } #region Windows 窗體設計器生成的代碼 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 = "已找到的素數:"; // 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 = "創(chuàng)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 = "掛起"; 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 = "恢復"; 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 = "銷毀"; 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 = "線程未啟動"; // // 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 = "素數"; this.Load += new System.EventHandler(this.Form1_Load); this.ResumeLayout(false); } #endregion /// <summary> /// 應用程序的主入口點。 /// </summary> [STAThread] static void Main() { Application.Run(new Form1()); } private void button1_Click(object sender, System.EventArgs e) { //創(chuàng)建線程實例,設置屬性 pNT = new Thread(new ThreadStart(GPN)); pNT.Name = "Prime Numbers Exaple"; pNT.Priority = ThreadPriority.BelowNormal; //設置按鍵,停用開始按鍵,啟用掛起按鍵和銷毀按鍵 button1.Enabled = false; button2.Enabled = true; button4.Enabled = true; //線程開始,并設置標識 pNT.Start(); pNTstart = true; } private void button2_Click(object sender, System.EventArgs e) { //設置掛起bool變量為真 suspend = true; //設置按鍵,停用掛起按鍵, 啟用恢復按鍵 button2.Enabled = false; button3.Enabled = true; } private void button3_Click(object sender, System.EventArgs e) { //設置掛起bool變量為假 suspend = false; //當線程當前狀態(tài)為掛起時,恢復該線程 if(pNT.ThreadState == System.Threading.ThreadState.Suspended || pNT.ThreadState == System.Threading.ThreadState.SuspendRequested) { try { //恢復線程 pNT.Resume(); //設置按鍵,停用恢復按鍵,啟用掛起按鍵 button3.Enabled = false; button2.Enabled = true; } catch(ThreadStateException Ex) { MessageBox.Show(Ex.ToString(), "提示"); } } } private void button4_Click(object sender, System.EventArgs e) { //設置按鍵,啟用開始按鍵,停用其他按鍵 button1.Enabled = true; button2.Enabled = false; button3.Enabled = false; button4.Enabled = false; //銷毀線程 pNT.Abort(); } //GPN為GetPrimeNumber的縮寫,用于查找并顯示素數 public void GPN() { //聲明變量 long Counter; //素數個數 long NumberNow; //當前數 long SqrtOfNow; //輔助數,做數組下標 bool IsPrime = false; //標識是否為素數 //數組,用于存儲已找到素數 long[] PrimeArray = new long[256]; //委托,用于顯示素數,即將其添加到ListBox中 string[] args = new string[] {"2"}; UD UIDel = new UD(UpdateUI); //初始化,從3開始計算,從第2個素數開始計算 NumberNow = 3; Counter = 2; //添加2為素數,放入素數數組并將其顯示 PrimeArray[1] = 2; this.Invoke(UIDel, args); //循環(huán),用于找到并輸出256個素數 while(Counter <= 255) { IsPrime = true; //從1到當前數的平方根,窮盡計算是否為素數 for(SqrtOfNow = 1; (PrimeArray[SqrtOfNow] * PrimeArray[SqrtOfNow] <= NumberNow); SqrtOfNow++) { //若能被已找到的素數整除,則不是素數 if(NumberNow % PrimeArray[SqrtOfNow] == 0) { //若不是素數,跳出for循環(huán) IsPrime = false; break; } } //若為素數,將其添加到ListBox以顯示 if(IsPrime) { //將素數存入數組中儲存 PrimeArray[Counter] = NumberNow; Counter++; //將素數顯示到ListBox中 args[0] = NumberNow.ToString(); this.Invoke(UIDel,args); //利用bool變量,控制是否掛起線程 if( suspend == true) { //調用Suspend方法,并捕捉異常 try { pNT.Suspend(); } catch(ThreadStateException Ex) { MessageBox.Show(Ex.ToString(), "提示"); } } //使線程睡眠,使過程清楚顯示,且有時間掛起線程 Thread.Sleep(500); } //除2外,素數必為奇數,故跳過偶數的檢查,優(yōu)化算法 NumberNow += 2; } } //更新ListBox的方法 void UpdateUI(string result) { listBox1.Items.Add(result); } //利用Timer控件顯示線程當前狀態(tài) private void timer1_Tick(object sender, System.EventArgs e) { //在線程開時候再獲取狀態(tài)并顯示 if( pNTstart ) { label2.Text = "線程當前狀態(tài)是:" + pNT.ThreadState.ToString(); } } private void Form1_Load(object sender, System.EventArgs e) { //設置按鍵,啟用開始按鍵,停用其他按鍵 button1.Enabled = true; button2.Enabled = false; button3.Enabled = false; button4.Enabled = false; } } }
感興趣的讀者可以動手調試一下該程序代碼,相信會有一定的啟發(fā)與借鑒價值。
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