实验二--语法分析程序的设计-

1、实验二 语法分析程序的设计姓名： 学号： 专业班级一、实验目的通过设计、编制、调试一个典型的语法分析程序，实现对词法分析程序所提供的单词序列进行语法检查和结构分析，进一步掌握常用的语法分析中预测分析方法。 二、实验内容设计一个文法的预测分析程序，判断特定表达式的正确性。三、实验要求1、 给出文法如下：GE E->T|E+T; T->F|T*F; F->i|(E);2、 根据该文法构造相应的LL(1)文法及LL(1)分析表，并为该文法设计预测分析程序，利用C语言或C+语言或Java语言实现；3、 利用预测分析程序完成下列功能：1） 手工将测试的表达式写入文本文件，每个

2、表达式写一行，用“；”表示结束；2） 读入文本文件中的表达式；3） 调用实验一中的词法分析程序搜索单词；4） 把单词送入预测分析程序，判断表达式是否正确（是否是给出文法的语言），若错误，应给出错误信息；5） 完成上述功能，有余力的同学可以进一步完成通过程序实现对非LL(1)文法到LL（1）文法的自动转换（见实验二附加资料1）。 四、实验环境PC微机DOS操作系统或 Windows 操作系统Turbo C 程序集成环境或 Visual C+ 程序集成环境 五、实验步骤1、 分析文法，将给出的文法转化为LL(1)文法；2、 学习预测分析程序的结构，设计合理的预测分析程序；3、

3、编写测试程序，包括表达式的读入和结果的输出；4、 测试程序运行效果，测试数据可以参考下列给出的数据。 六、测试数据 输入数据：编辑一个文本文文件expression.txt，在文件中输入如下内容：10;1+2;(1+2)*3+(5+6*7);(1+2)*3+4;1+2+3+(*4+5);(a+b)*(c+d);(ab3+de4)*5)+1;正确结果：（1）10;输出：正确（2）1+2;输出：正确（3）(1+2)*3+(5+6*7);输出：正确（4）(1+2)*3+4输出：错误（5）1+2+3+(*4+5)输出：错误（6）(a+b)*(c+d)输出：正确（7）(ab3+de4)*5)+

4、1输出：错误七、源代码import java.util.*;import java.io.*;public class test2 static String key_word = "main", "if", "then", "while", "do", "int","else" ;static String cal_word = "+", "-", "*", "/", &qu

5、ot;<", ">", "", "", "(",")", "", "", "=", "!=", "!", "=", ">=", "<=", "+=", "-=", "*=","/=", "" ;/* * 给

6、定文法GE： E->T|E+T; T->F|T*F; F->i|(E); */static String gram = "E->TA", "A->+TA", "A->", "T->FB", "B->*FB","B->", "F->P", "F->(E)" ;static String followE = ")", "#" ;stat

7、ic String followEA = ")", "#" ;static String followT = "+", ")", "#" ;static String followTB = "+", ")", "#" ;static String followF = "*", "+", ")", "#" ;static String firstE = &qu

8、ot;i", "(" ;static String firstEA = "+", "" ;static String firstT = "i", "(" ;static String firstTB = "*", "" ;static String firstF = "i", "(" ;static String list = "", "i", "+&quo

9、t;, "*", "(", ")", "#" , "E", "TA", null, null, "TA", null, null , "A", null, "+TA", null, null, "", "" , "T", "FB", null, null, "FB", null, null , "B"

10、;, null, "", "*FB", null, "", "" , "F", "i", null, null, "(E)", null, null ;public static void scan(String infile,String outfile, Stack<String> word, Stack<String> expression)throws Exception java.io.File file = new ja

11、va.io.File(infile);Scanner input = new Scanner(file);java.io.PrintWriter output = new PrintWriter(outfile);int count = 0;wordcount.push("#");while (input.hasNext() String tmp = input.next();int i = 0;while (i < tmp.length() if (tmp.charAt(i) <= '9' && tmp.charAt(i) &g

12、t;= '1') /检查十进制数字String num = ""while (tmp.charAt(i) <= '9' && tmp.charAt(i) >= '0') num += tmp.charAt(i);i+;if (i = tmp.length()break;output.println("< " + 1 + ", " + num + ">");wordcount.push("i");express

13、ioncount.push(num);if (i + 2 < tmp.length()/ 检查十六进制数字if (tmp.charAt(i) = '0' && tmp.charAt(i + 1) = 'x') i += 2;String num = ""while (tmp.charAt(i) <= '9' && tmp.charAt(i) >= '0') | (tmp.charAt(i) <= 'f' && tmp.cha

14、rAt(i) >= 'a') num += tmp.charAt(i);i+;if (i = tmp.length()break;output.println("< " + 3 + ", " + num + ">");wordcount.push("i");expressioncount.push(num);if (i + 1 < tmp.length()/ 检查八进制数字if (tmp.charAt(i) = '0') i+;String num = &qu

15、ot;"while (tmp.charAt(i) <= '7' && tmp.charAt(i) >= '0') num += tmp.charAt(i);i+;if (i = tmp.length()break;output.println("< " + 2 + ", " + num + ">");wordcount.push("i");expressioncount.push(num);/ 检查关键字和变量if (i < t

16、mp.length() if (i < tmp.length() && tmp.charAt(i) >= 'a'&& tmp.charAt(i) <= 'z') String tmp_word = ""while (tmp.charAt(i) >= 'a' && tmp.charAt(i) <= 'z') tmp_word += tmp.charAt(i);i+;if (i = tmp.length()break;boolean is

17、_keyword = false;for (int j = 0; j < key_word.length; j+) if (tmp_word.equals(key_wordj) output.println("< " + key_wordj + ", " + "->");wordcount.push(key_wordj);expressioncount.push(key_wordj);is_keyword = true;break;if (!is_keyword) output.println("<

18、" + 0 + ", " + tmp_word + ">");wordcount.push("i");expressioncount.push(tmp_word);/ 检查运算符以及''if (i < tmp.length() if (i + 1 < tmp.length() if (tmp.charAt(i + 1) = '=') for (int j = 0; j < cal_word.length; j+) if (cal_wordj.equals("&

19、quot; + tmp.charAt(i)+ tmp.charAt(i + 1) output.println("< " + cal_wordj + " ,"+ "->");wordcount.push(cal_wordj);expressioncount.push("-");if (wordcount.peek() = "") wordcount.pop();wordcount.push("#");count+;wordcount.push("#&qu

20、ot;);i += 2;break;for (int j = 0; j < cal_word.length; j+) if (cal_wordj.equals("" + tmp.charAt(i) output.println("< " + cal_wordj + ", " + "->");wordcount.push(cal_wordj);expressioncount.push(cal_wordj);if (wordcount.peek() = "") wordcount.

21、pop();wordcount.push("#");count+;wordcount.push("#");i+;break;input.close();output.close();public static void main(String args) throws Exception String infile = "D:/expression.txt"String outfile = "D:/result2.txt"Stack<String> tmpword = new Stack20;Stack

22、<String> expression = new Stack20;for (int i = 0; i < tmpword.length; i+) tmpwordi = new Stack<String>();expressioni = new Stack<String>();test1.scan(infile, outfile, tmpword, expression); int i = 0;while (tmpwordi.size() > 2)String tmp = expressioni.toArray(new String0);prin

23、tArray(tmp);isLL1(tmpwordi);i+;public static void printArray(String s)for (int i = 0; i < s.length; i+)System.out.print(si);System.out.println();public static void isLL1(Stack<String> tmpword)String input = tmpword.toArray(new String0);int inputCount = 0;Stack<String> status = new Sta

24、ck<String>();status.push(inputinputCount+);status.push("E");boolean flag = true;boolean result = true;while (flag) if (isVt(status.peek()if (status.peek().equals(inputinputCount)status.pop();inputCount+;elseflag = false;result = false;else if (status.peek().equals("#")if (status.peek().equals(inputinputCount)flag = false;elseflag = false;result = false;else if (listindexInList(status.peek(), inputinputC