import java.awt.*;
import java.applet.*;
public class Second extends Applet
{
private Label prompt1,prompt2,prompt3,prompt4,prompt5,prompt6,prompt7;
private Label LFunction1,LFunction2,LFunction3,LFunction4,LFunction5,LFunction6;
private TextField TFunction1,TFunction2,TFunction3,TFunction4,TFunction5,TFunction6;
private Label LX1,LY1,LX2,LY2;
private TextField TX1,TY1,TX2,TY2;
private Button BResult;
private TextField TvalX,TvalY;
private Label LCounter;
public void init()
{
this.setLayout(null);
prompt1 = new Label("利用数值方法中的割线法(Second Method)求方程式的解：");
prompt1.setBounds(10,0,400,20);
add(prompt1);
prompt2 = new Label("请输入以下方程式的系数：");
prompt2.setBounds(10,30,150,20);
add(prompt2);
LFunction1 = new Label("Y = ");
LFunction1.setBounds(10,60,20,20);
add(LFunction1);
TFunction1 = new TextField();
TFunction1.setBounds(40,60,30,20);
TFunction1.setText("0");
add(TFunction1);
LFunction2 = new Label("X^5 +");
LFunction2.setBounds(80,60,40,20);
add(LFunction2);
TFunction2 = new TextField();
TFunction2.setBounds(130,60,30,20);
TFunction2.setText("0");
add(TFunction2);
LFunction3 = new Label("X^4 +");
LFunction3.setBounds(170,60,40,20);
add(LFunction3);
TFunction3 = new TextField();
TFunction3.setBounds(220,60,30,20);
TFunction3.setText("0");
add(TFunction3);
LFunction4 = new Label("X^3 +");
LFunction4.setBounds(260,60,40,20);
add(LFunction4);
TFunction4 = new TextField();
TFunction4.setBounds(310,60,30,20);
TFunction4.setText("0");
add(TFunction4);
LFunction5 = new Label("X^2 +");
LFunction5.setBounds(350,60,40,20);
add(LFunction5);
TFunction5 = new TextField();
TFunction5.setBounds(400,60,30,20);
TFunction5.setText("0");
add(TFunction5);
LFunction6 = new Label("X +");
LFunction6.setBounds(440,60,20,20);
add(LFunction6);
TFunction6 = new TextField();
TFunction6.setBounds(470,60,30,20);
TFunction6.setText("0");
add(TFunction6);
prompt3 = new Label("请输入以下两点坐标，代表您要利用这两点求一个解：");
prompt3.setBounds(10,90,400,20);
add(prompt3);
LX1 = new Label("X1:");
LX1.setBounds(10,120,20,20);
add(LX1);
TX1 = new TextField("0");
TX1.setBounds(40,120,100,20);
add(TX1);
LY1 = new Label("Y1:");
LY1.setBounds(140,120,20,20);
add(LY1);
TY1 = new TextField("0");
TY1.setBounds(170,120,100,20);
TY1.setEditable(false);
add(TY1);
LX2 = new Label("X2:");
LX2.setBounds(280,120,20,20);
add(LX2);
TX2 = new TextField("0");
TX2.setBounds(310,120,100,20);
add(TX2);
LY2 = new Label("Y2:");
LY2.setBounds(410,120,20,20);
add(LY2);
TY2 = new TextField("0");
TY2.setBounds(440,120,100,20);
TY2.setEditable(false);
add(TY2);
BResult = new Button("求解");
BResult.setBounds(550,120,40,20);
add(BResult);
prompt4 = new Label("在两个 Y 值之间，乘积不需小于零，便可求出一解：");
prompt4.setBounds(10,150,300,20);
add(prompt4);
prompt5 = new Label("解为： X = ");
prompt5.setBounds(10,180,60,20);
add(prompt5);
TvalX = new TextField("0");
TvalX.setBounds(80,180,150,20);
TvalX.setEditable(false);
add(TvalX);
prompt6 = new Label("Y = ");
prompt6.setBounds(240,180,30,20);
add(prompt6);
TvalY = new TextField("0");
TvalY.setBounds(270,180,150,20);
TvalY.setEditable(false);
add(TvalY);
prompt7 = new Label("PS：此方法精确到小数点以下六位");
prompt7.setBounds(420,180,200,20);
add(prompt7);
LCounter = new Label("此方法共迭代了 0 次");
LCounter.setBounds(10,210,400,20);
add(LCounter);
}
public boolean action(Event e, Object o)
{
if(e.target instanceof TextField)
{
if(e.target == TX1)
{
System.out.println(TX1.getText());
TY1.setText(String.valueOf(runFunction(Double.valueOf(TX1.getText()).doubleValue())));
}
if(e.target == TX2)
{
System.out.println(TX2.getText());
TY2.setText(String.valueOf(runFunction(Double.valueOf(TX2.getText()).doubleValue())));
}
}
if(e.target == BResult)
{
double x1=0,x2=0,x3=0;
double Fx1=0,Fx2=0;
int counter=0;
x1 = Double.valueOf(TX1.getText()).doubleValue();
x2 = Double.valueOf(TX2.getText()).doubleValue();
Fx1 = runFunction(x1);
Fx2 = runFunction(x2);
x3 = ((x1*Fx2 - x2*Fx1)/(Fx2 - Fx1));
while((Math.abs(x1-x2) >= 0.000001)&&(counter<=60))
{
x3 = ((x1*Fx2 - x2*Fx1)/(Fx2 - Fx1));
x1 = x2;
x2 = x3;
Fx1 = runFunction(x1);
Fx2 = runFunction(x2);
counter ++;
LCounter.setText("此方法共迭代了"+counter+"次");
}
if(counter <=60)
{
TvalX.setText(String.valueOf(x1));
TvalY.setText(String.valueOf(runFunction(x1)));
}
else
{
TvalX.setText("可能无解");
TvalY.setText("可能无解");
LCounter.setText("此方法共迭代了"+counter+"次，但求不出解，请重新输入点坐标");
}
}
return true;
}
public double runFunction(double x)
{
double f;
f = Math.pow(x,5)*Double.valueOf(TFunction1.getText()).doubleValue()
+ Math.pow(x,4)*Double.valueOf(TFunction2.getText()).doubleValue()
+ Math.pow(x,3)*Double.valueOf(TFunction3.getText()).doubleValue()
+ Math.pow(x,2)*Double.valueOf(TFunction4.getText()).doubleValue()
+ Math.pow(x,1)*Double.valueOf(TFunction5.getText()).doubleValue()
+ Double.valueOf(TFunction6.getText()).doubleValue() ;
return f;
}
}
