编译原理词法分析实验报告java版.doc

. . 词法分析代码。 import java.io.*; import java.util.Vector; import java.util.regex.*; public class Compiler { public static String stringCompiler=; private static final String[] KEY_WORD={if, then, while, do, read, write,call, begin, end, const, var, procedure, odd}; private static boolean isKeyWord(String s) //是否是关键字 { boolean b=false; for(int i=0;iKEY_WORD.length;i++) if(s.equals(KEY_WORD[i])) b=true; return b; } class Element{ String s; String kind; String gets(){return s;} String getkind(){return kind;} Element(String s,String kind){ this.s = s; this.kind = kind; } } static VectorElement sheet = new VectorElement(8); File result = new File(result.txt); File result1 = new File(result1.txt); boolean work(){ System.out.println(输入PL/O语言为：); try{ FileWriter fw1 = new FileWriter(result1); BufferedWriter bw1 = new BufferedWriter(fw1); FileReader fr1 = new FileReader(input.txt); BufferedReader br1 = new BufferedReader(fr1); String s = br1.readLine(); label1: while(s!=null) { for(int i = 0;is.length();i++){ if(s.indexOf(//)!=-1) //两个/符 { s=s.substring(0, s.indexOf(//)); s=s.replaceAll(\t, ); s=s.replaceAll(\n, ); s=s.toLowerCase(); bw1.write(s); System.out.println(s); bw1.newLine(); s = br1.readLine(); continue label1; } else if(s.indexOf(/*)!=-1) // /符和*符 { s=s.substring(0,