编译语言-词法分析器的设计.doc

实验二 词法分析器的设计一、实验内容设计一个词法分析器程序，该程序能完成如下功能：输入的字符串中的单词有整数和以字母开头的标识符，分析器能识别出单词并区分是整数还是标识符，标识符中是否有while、do、if、then、else、begin、end、and、or、or等保留字。若单词是整数则输出整数的编码及数值，是标识符则判定是否为保留字，是保留字则将保留字及其对应的编码输出，否则输出标识符号及其编码。要求用JAVA语言、图形界面方式编程。（可参考实验指导书P110至P113）可以有如下约定：保留字if的编码为0，then为1，else为2，while为3，begin为4，do为5，end为6，and为39，or为40，not为41.整数的编码为57，标识符的编码为56.例如：若文本文件中的字符串为while do at a45 a+ 34 end 则输出(while,3), (do,5), (at,56), (a45,56), (a+,56), (34,57), (end,6)二、实验代码AnalysisOfMorphology.javapackage distinguish;import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.io.BufferedInputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;public class AnalysisOfMorphology extends JAppletprivate JFileChooser jfc = new JFileChooser(new File(.);private JTextArea jta1 = new JTextArea();private JTextArea jta2 = new JTextArea();private JButton jlb1 = new JButton(字符串的内容为：);private JButton jlb2 = new JButton(词法分析器分析结果为：);private JLabel fileName = new JLabel( Filename );private JTextField jtf = new JTextField(30);private JButton brower = new JButton(Brower);public AnalysisOfMorphology()JPanel p1 = new JPanel();p1.setLayout(new BorderLayout();p1.setBorder(BorderFactory.createEmptyBorder(5,5,5,10);p1.add(jlb1,BorderLayout.NORTH);p1.add(new JScrollPane(jta1), BorderLayout.CENTER);add(p1,BorderLayout.CENTER);JPanel p2 = new JPanel();p2.setLayout(new BorderLayout();p2.setBorder(BorderFactory.createEmptyBorder(5,5,5,10);p2.add(jlb2,BorderLayout.NORTH);p2.add(new JScrollPane(jta2), BorderLayout.CENTER);add(p2,BorderLayout.EAST);JPanel p3 = new JPanel();p3.setLayout(new BorderLayout();p3.add(fileName,BorderLayout.WEST);p3.add(jtf);p3.add(brower, BorderLayout.EAST);add(p3,BorderLayout.SOUTH);jtf.setText(C:/2.txt);brower.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e)open(););jtf.addKeyListener(new KeyAdapter() public void keyPressed(KeyEvent e) if(e.getKeyChar()=KeyEvent.VK_ENTER ) /按回车键执行相应操作; String file = jtf.getText(); try BufferedInputStream in = new BufferedInputStream(new FileInputStream(file); byte b = new bytein.available(); in.read(b,0,b.length); jta1.append(new String(b,0,b.length); in.close(); catch (IOException e1) jta1.setText(Error opening ); );jlb2.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e)String s = jta1.getText();jta2.setText(translateFigure(s););private String translateFigure(String string)String english = if,then,else,while,begin,do,end,and,or,not;int integer = 0,1,2,3,4,5,6,7,8,9;int figure = 0,1,2,3,4,5,6,39,40,41;String s = string;String str = ;String t = ;int n = 0;int j = 0;int k1 = 0;boolean flag = false;char ch = s.toCharArray(); for(int i = 0; i s.length(); i+) if(chi = |chi = .|chi = ,) t = s.substring(n, i); n = i+1; for(j = 0; j 10; j+) if(t.equals(englishj) str = str + ( + t + , + figurej + ) + , ; break; else if(t.substring(0,1).equals(+integerj) for(int k = 1; k t.length(); k+) for(k1 = 0; k1 =10) flag = false; break; if(flag) str = str + ( + t + , + 57 + ) + , ; else str = str + ( + t + , + -1 + ) + , ; break; if(j = 10) str = str + ( + t + , + 56 + ) + , ; str = str.substring(0, str.length()-3);return str;private void open()if(jfc.showOpenDialog(this) = JFileChooser.APPROVE_OPTION)open(jfc.getSelectedFile();private void open(File file)tryBufferedInputStream in = new BufferedInputStream(new FileInputStream(file);byte b = new bytein.available();in.read(b,0,b.length)