放一段代码

package sy1;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;

public class Bin {
   static char op[] = {'+','-','*','/','%'};
   //用于区分符号类别 
   static String[] mp= {"id","key","relop","界符","num","op"};
   //c是否是分界符 
   static int is_delim(char c) {
       if (c == ',' || c == ';' || c == '(' || c == ')' || c == '{' || c == '}' || c == '[' || c == ']') {
               return 1;
           }
           return 0;
   }
   //查找word是否在保留字表key中
   static int search_key(String word){
      //定义key表
       String[] key = {"void","main","short","long","int","double","float","while","if","else","for","break","return","char" };
       for (int i = 0; i < 14; i++) {
           if ( word.equals(key[i]) )
           //是保留字，返回1
             return 1;
       }
       //不是保留字，返回0
       return 0;
   }
   //c是否在op数组中 
   static int is_op(char c) {
       int p = -1;
       for(int i = 0; i < 4; i++) {
           if(c == op[i]) p = i;
       }
       return p;
   }
   public static void main(String []arg) {
      String file="input.txt";
       String word;
       String jz;
       int op_pos = -1;
       char ch;
       try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(
                        new FileInputStream("input.txt"),
                        StandardCharsets.UTF_8
                )
            );
             BufferedWriter outputFile = new BufferedWriter(
                new OutputStreamWriter(
                        new FileOutputStream("output.txt"),
                        StandardCharsets.UTF_8
                ),
                1024 * 8 * 8
             );
        ){ 
          StringBuffer sb = new StringBuffer();
          int chs=0;
            while ((chs = reader.read()) != -1) {
                sb.append((char) chs);
            }
            reader.close();
            String content= sb.toString();    
//            System.out.print(content);
         //第一个单词 
           int i=0;
          ch=content.charAt(i);
          while( i<content.length() ) {
          //识别分界符           
           if (is_delim(ch)==1) {
              outputFile.write("<"+ch+','+mp[3]+'>'+"\n");
               i++;
               if(i<content.length()) ch = content.charAt(i);//读取下一个 
               else {break;}
           }
           //识别数字 
         else if (Character.isDigit(ch)) {
               word = "";
               //连续的数字 
               while (Character.isDigit(ch)) {
                   word += ch;
                   i++;
                   ch = content.charAt(i);
                   if( Character.isDigit(ch) ) continue;
                   //如果出现小数点
                   if (ch == '.') {
                       word += ch;
                      i++;
                      ch = content.charAt(i);
                       //连续的数字 
                       if (Character.isDigit(ch)){                        
                           while(Character.isDigit(ch)) {
                               word += ch;
                              i++;
                              ch = content.charAt(i);
                           }
                           //num(实数) 
                           outputFile.write('<'+word+','+mp[4]+'>'+"\n");
                           break;
                       }
                       //如果小数点后没有数字，则报错
                       else 
                  {
                     //一直读取到这个错误的单词结束 
                     while(!Character.isDigit(ch)&&ch!=','&&ch!=';'&&ch!=')'&&ch!='+'&&ch!='-'&&ch!='*'&&ch!='/'&&ch!='='&&ch!='>'&&ch!='<'&&ch!='?'&&ch!='!'&&ch!='&'){
                        word += ch;
                              i++;
                              ch = content.charAt(i);
                        if(!(i<content.length())) break;
                     }
                     outputFile.write(word + " is error!\n");
                      break;
                  }    
                   }
               //如果数字后面是分界符或操作符，即为整数，作为常数存储 
               else if(ch==','||ch==';'||ch==')'||ch=='+'||ch=='-'||ch=='*'||ch=='/'||ch=='='||ch=='>'||ch=='<'||ch=='?'||ch=='!'||ch=='&'){
                  outputFile.write('<'+word+','+mp[4]+'>'+"\n");
                  break;    
               }
               //数字后面跟着字符，如8ws，则出错 
               else{
                  while(ch!=','&&ch!=';'&&ch!=')'&&ch!='+'&&ch!='-'&&ch!='*'&&ch!='/'&&ch!='='&&ch!='>'&&ch!='<'&&ch!='?'&&ch!='!'&&ch!='&'){
                     word += ch;
                           i++;
                           ch = content.charAt(i);
                     if(!(i<content.length())) break;
                  }
                  outputFile.write(word + " is error!\n");
                  break;
               }               
               }
           }
           
           //标志符可以以下划线/字母开始 
           //识别标识符/保留字
         else if (Character.isLetter(ch) || ch == '_') {
               word = "";
               while (Character.isLetter(ch) || Character.isDigit(ch) || ch =='_') {
                   word += ch;
                   i++;
                   ch = content.charAt(i);
               }
               //在key表中查找word是否是保留字
               if (search_key(word)==1) {
                  //保留字 
               outputFile.write('<'+word+','+ mp[1]+'>'+"\n");
               }
               //标识符
               else 
               outputFile.write('<'+word+','+mp[0]+'>'+"\n");
           }
           //复合运算符单独列出来处理 
         else if (ch == '>') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch == '=') {//">="
                   word += ch;
                   //读下一个单词，进入下一个循环 
                   i++;
                   ch = content.charAt(i);
               }
            outputFile.write('<'+word+','+mp[2]+'>'+"\n");
           }
           else if (ch == '<') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch == '=') {//"<="
                   word += ch;
                   i++;
                   ch = content.charAt(i);
               }
            outputFile.write('<'+word+','+mp[2]+'>'+"\n");
           }
           else if (ch == '&') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch == '&') {
                   word += ch;
                   i++;
                   ch = content.charAt(i);
               }
            outputFile.write('<'+word+','+mp[5]+'>'+"\n");
           }
           else if (ch == '|') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch == '|') {
                   word += ch;
                   i++;
                   ch = content.charAt(i);
               }
            outputFile.write('<'+word+mp[5]+'>'+"\n");
           }
           else if (ch == '!') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch != '=') {//"<="
               outputFile.write('<'+word+mp[5]+'>'+"\n");
               }            
               else if( ch == '=' ){//"!="
                   word += ch;
               outputFile.write('<'+word+mp[2]+'>'+"\n");
                   i++;
                   ch = content.charAt(i);
               }
           }

         else if (ch == '=') {
               word = "";
               word += ch;
                i++;
                ch = content.charAt(i);
               if (ch == '=') {//"=="
                   word += ch;
                   i++;
                   ch = content.charAt(i);
               }

            outputFile.write('<'+word+','+mp[2]+'>'+"\n");
           }        
           //其余的单个的运算符 
         else if((op_pos = is_op(ch)) != -1) {
               outputFile.write("<"+ch+','+mp[5]+'>'+"\n");   
                i++;
                ch = content.charAt(i);
           }
           //跳过空格 
         else {
                i++;
                ch = content.charAt(i);
           }
       }
      }catch (IOException e) {
           System.err.println("文件读取异常,请进行检查");
       }
   }
}