thdeeq.java

介绍了java的一些应用

/*
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 */

package ThDeEq;
import java.awt.*;
import java.awt.event.*;
/**
 *
 * @author liuwei
 */
public class ThDeEq extends WindowAdapter 
        implements  ActionListener
{
    Frame f=new Frame("一元三次方程解法器");
    Label lb1=new Label("X^3+");Label lb2=new Label("X^2+");
    Label lb3=new Label("X+");Label lb4=new Label("=0");
    TextField tf[]=new TextField[7];
    Button btn1=new Button("计算");Button btn2=new Button("清除");
    Label Rootlb[]=new Label[3];
    Panel p[]=new Panel[3];
    public ThDeEq(){
        int i;
        f.setLocation(400, 300);
        f.setSize(400,200);
        f.setLayout(new BorderLayout());
        f.addWindowListener(this);
        for(i=0;i<7;i++){
            tf[i]=new TextField(3);
        }
        //**************************************************************
        p[0]=new Panel();
        p[0].setSize(150,30);
        p[0].setLayout(new FlowLayout());
        p[0].add(tf[0]);p[0].add(lb1);p[0].add(tf[1]);p[0].add(lb2);p[0].add(tf[2]);
        p[0].add(lb3);p[0].add(tf[3]);p[0].add(lb4);
        p[0].setBackground(new Color(100,200,150));
        f.add(p[0],BorderLayout.NORTH);
        //**************************************************************
        p[1]=new Panel();
        p[1].setBackground(new Color(200,130,100));
        //p[1].setLocation(300, 300);
        p[1].setLayout(new GridLayout(3,2));
        for(i=0;i<3;i++){
           Rootlb[i]=new Label("X"+(i+1)+"=");
           p[1].add(Rootlb[i]);p[1].add(tf[i+4]);tf[i+4].setEditable(false);
        }
        f.add(p[1],BorderLayout.SOUTH);
        //**************************************************************
        p[2]=new Panel();
        p[2].setLayout(new FlowLayout());
        p[2].setBackground(new Color(250,200,240));
        p[2].add(btn1);p[2].add(btn2);
        f.add(p[2],BorderLayout.CENTER);
        btn1.addActionListener(new btn1ActionAdapter());
        btn2.addActionListener(new btn2ActionAdapter());
        //**************************************************************
        f.setVisible(true);
      }
        public static  void main(String[] args){
          new ThDeEq();  
        }
   public void windowClosing(WindowEvent we){
       System.exit(1);
   }
   class btn1ActionAdapter implements ActionListener{
   public void actionPerformed(ActionEvent ae) {
      double a,b,c,d;
      double A,B;
      double p,q,m;//(x+m)^3+p(x+m)+q=0
      double f,g;//a*(x-x1)(x^2+f*x+g)=0
      double x1,x2,x3;
      x1=0;x2=0;x3=0;
      int flag;
      a=Double.parseDouble(tf[0].getText());
      b=Double.parseDouble(tf[1].getText());
      c=Double.parseDouble(tf[2].getText());
      d=Double.parseDouble(tf[3].getText());
      if(a!=0)
    {
    m=b/3/a;
    p=b*b/3/a/a-c/a;
    q=m*m*m-p*m-d/a;
    A=-1*q/2-Math.pow((Math.pow(q/2,2)+Math.pow(p/3,3)),0.5);
    B=-1*q/2+Math.pow((Math.pow(q/2,2)+Math.pow(p/3,3)),0.5); 
    double A1,B1;
    if (A<=0)
    A1=-1*Math.pow(-1*A,1.0/3);
    else A1=Math.pow(A,1.0/3);
    if (B<=0)
    B1=-1*Math.pow(-1*B,1.0/3);
    else B1=Math.pow(B,1.0/3);
    x1=A1+B1-b/3/a;
    f=b/a+x1;
    g=c/a+f*x1;
    double delta=f*f-4*g;
    if(delta>=0)
	{
	x2=(-1*f+Math.sqrt(delta))/2;
	x3=(-1*f-Math.sqrt(delta))/2;
        flag=1;
	}
    else
    {
        flag=0;
    }
  }
  else
  {
      double delta1;
    delta1=c*c-4*b*d;
    if(b==0)
    {
        flag=-1;
        x1=-1*d/c;
    }
    if(delta1>=0)
    {
      x1=(-b+(double)Math.sqrt(delta1))/(2*b);  
      x2=(-b-(double)Math.sqrt(delta1))/(2*b); 
      flag=2;
    }
    else
        flag=-2;
  }
    //**************************************************************
       if(flag==-2)
        {
           tf[4].setText("NoRealRoot");tf[5].setText("NoRealRoot");
           tf[6].setText("NoRealRoot");
        }
        if(flag==-1)
        {
           tf[4].setText(""+x1);tf[5].setText("NoRealRoot");
           tf[6].setText("NoRealRoot");
        }
        if(flag==0)
        {
            tf[4].setText(""+x1);tf[5].setText("NoRealRoot");
           tf[6].setText("NoRealRoot");
        }
        if(flag==1)
        {
           tf[4].setText(""+x1);tf[5].setText(""+x2);
           tf[6].setText(""+x3);
        }
        if(flag==2)
        {
            tf[4].setText(""+x1);tf[5].setText(""+x2);
           tf[6].setText(""+x3);
        }
   }
   }
   class btn2ActionAdapter implements ActionListener{
       public void actionPerformed(ActionEvent ae){
           int j;
           for(j=0;j<7;j++){
               tf[j].setText("");
           }
       }
   }

    public void actionPerformed(ActionEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
}