Flash版的拉格朗日插值程序

依次输入n,x,x[i],y[i]，输一个打个回车。

下面是另一种风格





源代码：

请用NeoSwiff C#编译器编译，编译的结果是生成flash

 

/**//*
|
| ZhangLi CopyRight 2005
|
*/


using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;



namespace eval
{




  public class Form1 : System.Windows.Forms.Form
  {

    private System.Windows.Forms.TextBox CommandBox=null;
    private System.Windows.Forms.TextBox InputBox=null;

    
      double[] y;
      double[] x;
      int n;
      int i=0;
      double xx,yy;
      int state=0;

    public Form1()
    {
      InitializeComponent();
      

    }

    private void InitializeComponent()
    {
      
      this.CommandBox=new System.Windows.Forms.TextBox();
      this.InputBox=new System.Windows.Forms.TextBox();

      this.SuspendLayout();
      
      
     this.CommandBox.Multiline=true;
     this.CommandBox.ReadOnly=true;
     this.CommandBox.ScrollBars=System.Windows.Forms.ScrollBars.Vertical;
     this.CommandBox.Text="Lagrange interpolation Demo Program\nZhangLi CopyRight 2005\nhttp://www.cnblogs.com/jonlee\n\nn=";
     this.CommandBox.BackColor=System.Drawing.Color.Black;//是否黑底
     this.CommandBox.ForeColor=System.Drawing.Color.White;//是否白字
     this.CommandBox.Location=new System.Drawing.Point(0,0);
     this.CommandBox.Width=400;
     this.CommandBox.Height=275;    
     
      
     this.InputBox.Multiline=false;
     this.InputBox.Location=new System.Drawing.Point(0,275);
     this.InputBox.Width=400;
     this.InputBox.Height=25;
     this.InputBox.KeyPress += new KeyPressEventHandler(getCommand);
     this.InputBox.MouseDown += new System.Windows.Forms.MouseEventHandler(TMouseDown);
     this.InputBox.Text="Enter the number here";

    



      this.Controls.Add(this.CommandBox);
       this.Controls.Add(this.InputBox);

      //设置“平面”样式
      //System.Windows.Forms.Skins.Flat.FlatSkin fsk=null;
      //fsk=new System.Windows.Forms.Skins.Flat.FlatSkin();
      //this.Skin=fsk;
     
      this.Text = "Form1";
      this.BackColor=System.Drawing.Color.White;
      this.ResumeLayout(false);
      
      y=new double[100];
      x=new double[100];
      
    
         
      
      
    }
    
    private void TMouseDown( Object sender, MouseEventArgs e )
    {
        if(this.InputBox.Text=="Enter the number here")
        {
            this.InputBox.Text="";
        }
    }

    private void getCommand( object sender, KeyPressEventArgs e )
    {
        if(e.KeyChar=='\r')
        {

        
            this.CommandBox.Text+=this.InputBox.Text;

            
            if(state==0)
            {
                n=System.Int32.Parse(this.InputBox.Text);
                this.CommandBox.Text+="\nx=";
            
            }
            else if(state==1)
            {
                xx=System.Double.Parse(this.InputBox.Text);
                this.CommandBox.Text+="\nxi=";                
                
            }
            else if(state%2==0 && i<n)
            {
                x[i]=System.Double.Parse(this.InputBox.Text);
                this.CommandBox.Text+="\nyi=";
            }
            else if(i<n)
            {
                y[i]=System.Double.Parse(this.InputBox.Text);
                if(i<n-1)
                {
                    this.CommandBox.Text+="\nxi=";    
                    ++i;
                }
                else
                {
                    yy=Lagrange(x,y,xx,n);
                    this.CommandBox.Text+="\nResult: x="+ xx.ToString() +" y="+yy.ToString()+"\n";
                    i=0;
                    state=-1;
                    this.CommandBox.Text+="\nn=";
                }
                            
            }

                
            ++state;
            this.InputBox.Text="";
            this.CommandBox.ScrollToBottom();
        }
    }
    
    
   private double Lagrange(double[] x,double[] y,double xx,int n)
    {
        double p;
        double yx=0;

        for(int k=0;k<n;++k)
        {
            p=1;

            for(int j=0;j<n;++j)
            {
                if(j!=k)
                {
                    p = p * ( xx - x[j] ) / ( x[k] - x[j] );
                }
            }

            yx = yx + p * y[k];
        }

        return yx;
    }
    
    
    
    

    static void Main()
    {
    
       System.Environment.FSCommand("Allowscale","false");
       System.Environment.FSCommand("showmenu","false");
      
      Application.Run( new Form1() );

    }
  }
}

工程文件下载（Visual Studio 2003版本）

  
因为这个算法实现比较简单，所以我想到用这种特别方法来做实验，其实也说明了很多算法是可以独立于具体语言的。