example1_10.java

清华大学2002年出版的《科学与工程数值计算算法Java》配套源码

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

class Complex
{ double real,image;
  public static void init(double a,double b,Complex c)
  {c.real=a;c.image=b;}
 public static void chu(Complex a,Complex b,Complex c)
   { double w;
     if(Math.abs(b.real)>Math.abs(b.image))
     {w=b.real+b.image*(b.image/b.real);
      c.real=(a.real+a.image*(b.image/b.real))/w;
      c.image=(a.image-a.real*(b.image/b.real))/w;
     }
     else
 	{w=b.real*(b.real/b.image)+b.image;
 	 c.real=(a.real*(b.real/b.image)+a.image)/w;
 	 c.image=(a.image*(b.real/b.image)-a.real)/w;
     }
 }
 public static void Tan(Complex a)
 { Complex as,ac;
   as=new Complex();ac=new Complex();
   double x,y;
   y=Math.exp(a.image);x=a.real;
   ac.real=Math.cos(x)*(y+1.0/y)/2;ac.image=Math.sin(x)*(1.0/y-y)/2;
   as.real=Math.sin(x)*(y+1.0/y)/2;as.image=Math.cos(x)*(y-1.0/y)/2;
   Complex.chu(as,ac,a);
 }

}

public class Example1_10 extends Applet implements ActionListener
{TextField text1,text2;
 TextArea text3;
 Button button1;
 public void init()
 {text1=new TextField(10);text2=new TextField(10);text3=new TextArea(10,50);
  button1=new Button("计算正切");
  add(text1);add(text2);add(button1);add(text3);
  text3.setEditable(false);
  button1.addActionListener(this);
 }
 public void actionPerformed(ActionEvent e)
 {double n1,n2;
  Complex a;
  if(e.getSource()==button1)
  {n1=Double.valueOf(text1.getText()).doubleValue();
   n2=Double.valueOf(text2.getText()).doubleValue();
   a=new Complex();Complex.init(n1,n2,a);
   text3.setText("");
   text3.append("复数A=("+a.real+")+("+a.image+")I\n");
   Complex.Tan(a);
   text3.append("它的正切:\nTanA=("+a.real+")+("+a.image+")I\n");
   }
 }
}