用JAVA写词法分析器

import java.lang.*;import java.io.*;public class Wordanalsys static char ch; static int index=0; static int j=0; static char allstr=new char; static String name; public char Getchar() try ch=(char)System.in.read(); catch(Exception e)e.printStackTrace(); return ch; public boolean IsLetter(char ch) return java.lang.Character.isLetter(ch); public boolean IsDigit(char ch) return java.lang.Character.isDigit(ch); public int Reserve() KeyTable table=new KeyTable5; table0=new KeyTable(while,1); table1=new KeyTable(for,2); table2=new KeyTable(if,3); table3=new KeyTable(else,4); table4=new KeyTable(int,5); name=new String(allstr).substring(j,index);/取子串 for(int i=0;i5;i+) if(name.equals(tablei.key) return tablei.code; return 0; public static void main (String args) Wordanalsys a=new Wordanalsys(); ch=a.Getchar(); int m=0; while(ch!=#) allstrindex=ch; index+; ch=a.Getchar(); int k=index; index=0; while(jk-1) m=j; if(a.IsLetter(allstrj) while(a.IsLetter(allstrindex)|a.IsDigit(allstrindex) index+; if(a.Reserve()!=0) System.out.println(保留字 +name+ +a.Reserve(); else System.out.println(标识符 + 6); j=index; if(a.IsDigit(allstrj) while(a.IsDigit(allstrindex)index+; name=new String(allstr).substring(j,index); int b=java.lang.Integer.pasint(name); String name1=Integer.toBinaryString(b) ; System.out.println(数字 +name+ 7+name1); j=index; if(allstrj=()System.out.println(左括号 +( 8);index+;j=index; if(allstrj=)System.out.println( 等号 += 9);index+;j=index; if(allstrj=)System.out.println(右括号 +) 10);index+;j=index; if(allstrj= )while(allstrj= )index+;j=index; if(allstrj=;)System.out.println(分号+ ; 11);index+;j=index; if(allstrj=)index+;j=index; if(allstrj=) System.out.println(小于等于+ = 12);index+;j=index; else System.out.println(小于 + )index+;j=index; if(allstrj=) System.out.println(大于等于+ = 15);index+;j=index ; elseSystem.out.println(大于号+ 14 ); if(allstrj=+)index+;j=index; if(allstrj=+) System.out.println(自增运算符+ + 16);index+;j=index; else System.out.println(加号+ + 17); if(allstrj=-)index+;j=index; if(allstrj=-) System.out.println(自减运算符+ - 16);index+;j=index; else System.out.println(减号+ - 17); if(allstrj=n)System.out.println(enter the next line);index+;j=index; if(m=j)System.out.println(the illegal character +allstrj