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

class YourWindow extends Frame implements ActionListener {
    TextField text1, text2, text3, text4;
    Button b1;

    YourWindow(String s) {
        super(s);
        setLayout(new FlowLayout());
        text1 = new TextField(20);
        text2 = new TextField(20);
        text3 = new TextField("输入明文", 20);
        text4 = new TextField("输入密文", 20);
        text3.setEditable(false);
        text4.setEditable(false);
        b1 = new Button("退出");
        add(text1);
        add(text2);
        add(text3);
        add(text4);
        add(b1);
        b1.addActionListener(this);
        text1.addActionListener(this);
        text2.addActionListener(this);
        setBounds(200, 200, 550, 350);
        setVisible(true);
        validate();
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == b1) {
            System.exit(0);
        } else if (e.getSource() == text1) {
            String s = text1.getText();
            convertString(s);
            char n[] = s.toCharArray();
            int i;
            int m = 0;
            char k[] = new char[n.length];
            for (i = 0; i < n.length; i++) {
                m = (int) n[i];
                if ((m + 1) <= 90 && (m + 1) >= 65) {
                    k[i] = (char) (m + 1);
                } else if ((m + 1) > 90) {
                    k[i] = (char) (m + 1 - 26);
                }
            }
            text2.setText(String.valueOf(k));
        } else if (e.getSource() == text2) {
            String ss = text2.getText();
            convertString(ss);
            char nn[] = ss.toCharArray();
            int ii;
            int mm = 0;
            char kk[] = new char[nn.length];
            for (ii = 0; ii < nn.length; ii++) {
                mm = (int) nn[ii];
                if ((mm - 1) > 0) {
                    kk[ii] = (char) (mm - 1);
                } else if ((mm - 1) <= 0) {
                    kk[ii] = (char) (mm - 1 + 26);
                }
                text1.setText(String.valueOf(kk));
            }
        }
    }

    public static String convertString(String src) {
        char[] array = src.toCharArray();
        int temp = 0;
        for (int i = 0; i < array.length; i++) {
            temp = (int) array[i];
            if (temp <= 90 && temp >= 65) { // array[i]为大写字母
                array[i] = (char) (temp + 32);
            }
            // else if{}
        }
        return String.valueOf(array);
    }
}

public class Acc {
    public static void main(String args[]) {
        YourWindow a = new YourWindow("解密");
    }
}