此类从JPanel GUI读取输入。除非我为每个系数输入1，否则不会SOP。然后它只打印“0.0”任何关于如何让它工作的建议？我已经尝试了我能想到的一切。
public class PolyRoots extends PolyGUI {
private double coefficientToFifthPower;
private double coefficientToFourthPower;
private double coefficientToThirdPower;
private double coefficientToSecondPower;
private double coefficientToFirstPower;
private double constant;
private double x;
public double getCoefficientToFifthPower() {
return coefficientToFifthPower;
}
public void setCoefficientToFifthPower(double coefficientToFifthPower) {
this.coefficientToFifthPower = coefficientToFifthPower;
}
public double getCoefficientToFourthPower() {
return coefficientToFourthPower;
}
public void setCoefficientToFourthPower(double coefficientToFourthPower) {
this.coefficientToFourthPower = coefficientToFourthPower;
}
public double getCoefficientToThirdPower() {
return coefficientToThirdPower;
}
public void setCoefficientToThirdPower(double coefficientToThirdPower) {
this.coefficientToThirdPower = coefficientToThirdPower;
}
public double getCoefficientToSecondPower() {
return coefficientToSecondPower;
}
public void setCoefficientToSecondPower(double coefficientToSecondPower) {
this.coefficientToSecondPower = coefficientToSecondPower;
}
public double getCoefficientToFirstPower() {
return coefficientToFirstPower;
}
public void setCoefficientToFirstPower(double coefficientToFirstPower) {
this.coefficientToFirstPower = coefficientToFirstPower;
}
public double getConstant() {
return constant;
}
public void setConstant(double constant) {
this.constant = constant;
}
private double y;
public void readInputCoefficients() {
/* this.coefficientToFifthPower = Integer.parseInt(inputCoefficientFifthPower);
this.coefficientToFourthPower = Integer.parseInt(inputCoefficientFourthPower);
this.coefficientToThirdPower = Integer.parseInt(inputCoefficientThirdPower);
this.coefficientToSecondPower = Integer.parseInt(inputCoefficientSecondPower);
this.coefficientToFirstPower = Integer.parseInt(inputCoefficientFirstPower);
this.constant = Integer.parseInt(inputConstant);*/
}
public double calculateY(double x) {
this.y = this.coefficientToFifthPower * Math.pow(x, 5) + this.coefficientToFourthPower * Math.pow(x, 4) +
this.coefficientToThirdPower * Math.pow(x, 3) + this.coefficientToSecondPower * Math.pow(x, 2) + (this.coefficientToFirstPower * x) + this.constant;
return this.y;
}
public void getTheBounds() {
for (double x = -10.0001; x <= 10.0001; x += .1) {
double y1 = calculateY(x);
double y2 = calculateY(x + .01);
if ((y1 * y2) < 0) {
System.out.println(bisectionMethod(y1, y2));
}
else if((y1 * y2) > 0){
System.out.println(bisectionMethod(y1,y2));
}
}
}
public double bisectionMethod(double a, double b) {
double average;
double root = 0;
double yOfC;
int leaveloop = 0;
for(int x = 0; x <= 10000000; x++) {
average = (a + b) / 2;
yOfC = calculateY(average);
if (Math.abs(yOfC) < 0.0001) {
root = average;
return root;
} else if (yOfC * calculateY(a) > 0) {
a = average;
} else {
b = average;
}
}
System.out.println(root);
return root;
}
}
GUI
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;
public class PolyGUI extends JPanel
{
// ***Variables are created ***
//*** GUIs are made up of JPanels. Panels are created
//*** here and named appropriately to describe what will
//*** be placed in each of them.
JPanel titlePanel = new JPanel();
JPanel c5Panel = new JPanel();
JPanel c4Panel = new JPanel();
JPanel c3Panel = new JPanel();
JPanel c2Panel = new JPanel();
JPanel c1Panel = new JPanel();
JPanel cPanel = new JPanel();
JPanel calculatePanel = new JPanel();
//*** a JLabel is a text string that is given a String value
//*** and is placed in its corresponding JPanel or JButton
JLabel titleLabel = new JLabel();
JLabel c5Label = new JLabel();
JLabel c4Label = new JLabel();
JLabel c3Label = new JLabel();
JLabel c2Label = new JLabel();
JLabel c1Label = new JLabel();
JLabel cLabel = new JLabel();
JLabel questionLabel = new JLabel();
JLabel calculateLabel = new JLabel();
//*** three JButtons are created. When pushed, each button calls
//*** its corresponding actionPerformed() method from the class created
//*** for each button. This method executes the method code, performing
//*** what the button is to do.
JButton calculateButton = new JButton();
//*** a JTextField creates a location where the client can place
//*** text
JTextField x5Txt = new JTextField(8);
JTextField x4Txt = new JTextField(8);
JTextField x3Txt = new JTextField(8);
JTextField x2Txt = new JTextField(8);
JTextField xTxt = new JTextField(8);
JTextField constantTxt = new JTextField(8);
//*** constructor
//*** Variables are given initial values
public PolyGUI()
{
//*** set panel layouts
//*** panels could be LEFT, or RIGHT justified.
titlePanel.setLayout(new FlowLayout(FlowLayout.CENTER));
c5Panel.setLayout(new FlowLayout(FlowLayout.CENTER));
c4Panel.setLayout(new FlowLayout(FlowLayout.CENTER));
c3Panel.setLayout(new FlowLayout(FlowLayout.CENTER));
c2Panel.setLayout(new FlowLayout(FlowLayout.CENTER));
c1Panel.setLayout(new FlowLayout(FlowLayout.CENTER));
cPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
questionLabel.setLayout(new FlowLayout(FlowLayout.CENTER));
calculateButton.setLayout(new FlowLayout(FlowLayout.CENTER));
//*** set Label fonts. You can use other numbers besides 30,20
//*** or 15 for the font size. There are other fonts.
Font quizBigFont = new Font("Helvetica Bold", Font.BOLD, 30);
Font quizMidFont = new Font("Helvetica Bold", Font.BOLD, 20);
titleLabel.setFont(quizBigFont);
questionLabel.setFont(quizMidFont);
c5Label.setFont(quizMidFont);
c4Label.setFont(quizMidFont);
c3Label.setFont(quizMidFont);
c2Label.setFont(quizMidFont);
c1Label.setFont(quizMidFont);
cLabel.setFont(quizMidFont);
//*** labels are given string values
titleLabel.setText("Polynomial Project");
questionLabel.setText("Please enter the coefficients");
c5Label.setText("5");
c4Label.setText("4");
c3Label.setText("3");
c2Label.setText("2");
c1Label.setText("1");
cLabel.setText("constant");
calculateButton.setText("Calculate");
calculateButton.addActionListener(new calculate());
//*** panels
titlePanel.add(titleLabel);
c5Panel.add(c5Label);
c5Panel.add(x5Txt);
c4Panel.add(c4Label);
c4Panel.add(x4Txt);
c3Panel.add(c3Label);
c3Panel.add(x3Txt);
c2Panel.add(c2Label);
c2Panel.add(x2Txt);
c1Panel.add(c1Label);
c1Panel.add(xTxt);
cPanel.add(cLabel);
cPanel.add(constantTxt);
calculatePanel.add(calculateButton);
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
add(titlePanel);
add(questionLabel);
add(c5Panel);
add(c4Panel);
add(c3Panel);
add(c2Panel);
add(c1Panel);
add(cPanel);
add(calculatePanel);
//*** The method writeToFile() is called from the constructor.
//*** One could call a read method from the constructor.
// writeToFile();
}// constructor
public void display()
{ //*** A JFrame is where the components of the screen
//*** will be put.
JFrame theFrame = new JFrame("GUI Example");
//*** When the frame is closed it will exit to the
//*** previous window that called it.
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//*** puts the panels in the JFrame
theFrame.setContentPane(this);
//*** sets the dimensions in pixels
theFrame.setPreferredSize(new Dimension(600, 380));
theFrame.pack();
//*** make the window visible
theFrame.setVisible(true);
}
class calculate implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
System.out.println("Calculating...");
PolyRoots p1 = new PolyRoots();
double x5 = Integer.parseInt(x5Txt.getText());
double x4 = Integer.parseInt(x4Txt.getText());
double x3 = Integer.parseInt(x3Txt.getText());
double x2 = Integer.parseInt(x2Txt.getText());
double x = Integer.parseInt(xTxt.getText());
double constant = Integer.parseInt(constantTxt.getText());
p1.setCoefficientToFifthPower(x5);
p1.setCoefficientToFourthPower(x4);
p1.setCoefficientToThirdPower(x3);
p1.setCoefficientToSecondPower(x2);
p1.setCoefficientToFirstPower(x);
p1.setConstant(constant);
p1.getTheBounds();
}
}
public static void main(String[] args) throws IOException
{
PolyGUI newGUI = new PolyGUI();
newGUI.display();
}
}
答案 0 :(得分：0)
以下是一个程序的简单示例，其中包含main，您可以看到每行代码的作用。
public class PolyRoots {
private final double[] coeffs; // any number of coefficients.
public PolyRoots(double... coeffs) {
this.coeffs = coeffs;
}
public double calcY(double x) {
double ret = coeffs[0];
for (int i = 1; i < coeffs.length; i++)
ret = ret * x + coeffs[i];
return ret;
}
public static void main(String[] args) {
PolyRoots roots = new PolyRoots(1e-3, -2e-2, 0.1, -1, 5);
for (int i = -10_000; i <= 10_000; i++) {
double x = i / 1000.0;
double y = roots.calcY(x);
System.out.println(x + "\t" + y);
}
}
}
对于这样的程序，您可以添加getBounds和bisectionMethod但是这些方法确实可以做到他们应该做的事情（因为我无法弄清楚他们甚至想做什么，但我有只发展了三十年;）