import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Equation {
JLabel l1 = new JLabel("请输入一元二次方程各项的系数:", JLabel.CENTER);
JTextField t1 = new JTextField(10);
JTextField t2 = new JTextField(10);
JTextField t3 = new JTextField(10);
JButton but1 = new JButton("求解");
JButton but2 = new JButton("重置");
public Equation() {
JFrame f = new JFrame();
l1.setFont(new Font("华文行楷", Font.PLAIN, 24));
l1.setForeground(Color.blue);
JLabel l2 = new JLabel("二次项系数:");
JLabel l3 = new JLabel("一次项系数:");
JLabel l4 = new JLabel("常数项 :");
Container c = f.getContentPane();
c.setLayout(new GridLayout(6, 1));
JPanel p2 = new JPanel(new FlowLayout());
JPanel p3 = new JPanel(new FlowLayout());
JPanel p4 = new JPanel(new FlowLayout());
JPanel p5 = new JPanel(new FlowLayout());
JPanel p6 = new JPanel(new FlowLayout());
p2.add(l1);
p3.add(l2);
p3.add(t1);
p4.add(l3);
p4.add(t2);
p5.add(l4);
p5.add(t3);
p6.add(but1);
p6.add(but2);
c.add(p2);
c.add(p3);
c.add(p4);
c.add(p5);
c.add(p6);
f.setTitle("求一元二次方程的解");
f.setBounds(200, 200, 400, 280);
f.setVisible(true);
f.setResizable(false);
// 设置按钮but1的按钮事件
but1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (t1.getText().equals("") | t2.getText().equals("")
| t3.getText().equals("")) {
JOptionPane.showMessageDialog(null, "请输入方程各项的系数!", "警告",
JOptionPane.WARNING_MESSAGE);
}
double a = Double.parseDouble(t1.getText());
double b = Double.parseDouble(t2.getText());
double c = Double.parseDouble(t3.getText());
double m = Math.pow(b, 2) - 4 * a * c;
double n1 = (-b + Math.sqrt(m)) / 2 * a;
double n2 = (-b - Math.sqrt(m)) / 2 * a;
if (m < 0) {
JOptionPane.showMessageDialog(null, "该方程无实根", "提示信息",
JOptionPane.INFORMATION_MESSAGE);
} else if (m == 0) {
JOptionPane.showMessageDialog(null, "该方程有两个相等的实根" + '\n'
+ "x1 = x2 = " + n1, "提示信息",
JOptionPane.INFORMATION_MESSAGE);
} else {
JOptionPane.showMessageDialog(null, "该方程有两个不相等的实根" + '\n'
+ "x1 = " + n1 + " " + "x2=" + n2, "提示信息",
JOptionPane.INFORMATION_MESSAGE);
}
}
});
// 设置按钮but2的按钮事件
but2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
t1.setText("");
t2.setText("");
t3.setText("");
}
});
}
public static void main(String args[]) {
Equation e = new Equation();
}
}
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