采用状态机的设计思路，实现一个去注释的小程序；去掉/**/和//两种注释：
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1 package com.app;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.io.FileNotFoundException;
6 import java.io.FileOutputStream;
7 import java.io.FileWriter;
8 import java.io.IOException;
9 import java.io.InputStream;
10 import java.io.InputStreamReader;
11 import java.io.OutputStream;
12 import java.io.OutputStreamWriter;
13 import java.io.Reader;
14 import java.io.Writer;
15 import java.util.Stack;
16
17 public class app {
18 public enum stype{
19 stype_type1, //当前是/*
20 stype_type2, //当前是//
21 stype_type3, //当前是数据
22 }
23
24 private static stype app_stype;
25
26 public app(){
27 app_stype = stype.stype_type3;
28 }
29
30 /**
31 * @param args
32 */
33 public static void main(String[] args) {
34 // TODO Auto-generated method stub
35 try{
36 File Orifile = new File(app.class.getResource("main.cpp").getFile());
37 File Desfile = new File("bak_" + Orifile.getName().toString());
38
39 InputStream in = new FileInputStream(Orifile);;
40
41 Reader reader = new InputStreamReader(in);
42 FileWriter fw = new FileWriter(Desfile);
43
44 int curtemp = 0;
45 int pretemp = 0;
46
47 while((curtemp = reader.read()) != -1){
48
49 if(app_stype == stype.stype_type1){
50 if(('*' == pretemp)&&('/' == curtemp)){
51 app_stype = stype.stype_type3;
52 }
53 }else if(app_stype == stype.stype_type2){
54 if(('\n' == curtemp)&&('\r' == pretemp)){
55 app_stype = stype.stype_type3;
56 }
57 }else{
58 if(('/' == pretemp)&&('*' == curtemp)){
59 app_stype = stype.stype_type1;
60 }else if(('/' == pretemp)&&('/' == curtemp)){
61 app_stype = stype.stype_type2;
62 }else{
63 if(('/' != curtemp)&&('*' != curtemp)){
64 if(('/' == pretemp)&&('*' == pretemp)){
65 fw.write(pretemp);
66 }
67 fw.write(curtemp);
68 }
69 }
70 }
71
72 pretemp = curtemp;
73 }
74
75 fw.flush();
76 fw.close();
77 in.close();
78
79
80 } catch (FileNotFoundException e) {
81 // TODO Auto-generated catch block
82 e.printStackTrace();
83 } catch (IOException e) {
84 // TODO Auto-generated catch block
85 e.printStackTrace();
86 }
87
88 }
89
90 }