以下两则代码均是在向论坛上的高手们学习之后模仿出的结果，而自己之前写的那叫个臭呀！
代码1
1
/**//*
2
* 用状态机实现对代码中注释的清除.
3
*/
4
5#include <stdio.h>
6#include <string.h>
7
8#define SCREEN
9
10void initialize_fsm(char fsm[7][256]);
11
12int main()
13
{
14 int ch , temp = 0 ;
15 int state = 0;
16 char fsm[7][256];
17
18 FILE *pfin ;
19 if ((pfin = fopen("sweep-comments.txt","r")) == NULL)
20
{
21 printf("can not open the file");
22 exit(0);
23
}
24
25 #ifdef SCREEN
26 #define OUT stdout
27 #else
28 FILE *pfout;
29 pfout = fopen("result.txt","w");
30 #define OUT pfout
31 #endif
32
33 initialize_fsm(fsm);
34
35 #pragma region FSM /**////尝试#pragma region功能. Visual C++ 2005
36
37 while ((ch = fgetc(pfin)) != EOF)
38 {
39 state = fsm[state][ch];
40
41 if ( state != 2 && ch !='*' && temp == '/')
42 fputc(temp,OUT);
43
44 temp = ch;
45
46 switch(state)
47 {
48 /**//*0,5,6执行同一个动作*/
49 case 5:
50 case 6:
51 case 0:
52 fputc(ch,OUT);
53 break;
54 case 7:
55 state = 0;
56 break;
57 }
58
59 if(state != 1)
60 temp=0;
61 }
62 #pragma endregion
63}
64
65void initialize_fsm(char fsm[7][256])
66{
67 int lenth = sizeof(char)*256;
68
69 memset(fsm[0],0,lenth);
70 memset(fsm[1],0,lenth);
71 memset(fsm[2],2,lenth);
72 memset(fsm[3],3,lenth);
73 memset(fsm[4],3,lenth);
74 memset(fsm[5],5,lenth);
75 memset(fsm[6],5,lenth);
76
77 fsm[0]['"'] = 5;
78 fsm[0]['/'] = 1;
79 fsm[1]['/'] = 2;
80 fsm[1]['*'] = 3;
81 fsm[2]['\n'] = 0;
82 fsm[3]['*'] = 4;
83 fsm[4]['/'] = 7;
84 fsm[5]['\\'] = 6;
85 fsm[5]['"'] = 0;
86}
87
代码2
1%{
2/**//*
3*用lex实现清除代码注释
4*/
5void comment(int style);
6void string_constant();
7const int singalline =0, multiline =1;
8
9%}
10
11
12%%
13
14"/*" {comment(multiline );}
15"//" {comment(singalline);}
16"\"" {string_constant();}
17.|\n {fprintf(yyout,"%c",*yytext);}
18
19%%
20
21int main(int argc,char *argv[])
22{
23 FILE *pfin ,*pfout;
24 if ((pfin = fopen (argv[1],"r")) ==NULL)
25 {
26 printf("can not open the file\n");
27 exit (1);
28 }
29 pfout = fopen("output.txt","w");
30
31 yyin = pfin;
32 yyout = pfout;
33
34 yylex();
35
36 return 0;
37}
38
39void string_constant()
40{
41 int ch ;
42
43 fprintf(yyout,"%c",*yytext);
44
45 while ( (ch = input()) != EOF)
46 {
47 if (ch == '\\')
48 {
49 fprintf(yyout,"%c",ch);
50 ch = input();
51 fprintf(yyout,"%c",ch);
52
53 continue;
54 }
55
56 if (ch == '\"')
57 {
58 fprintf(yyout,"%c",ch);
59 break;
60 }
61
62 fprintf(yyout,"%c",ch);
63 }
64}
65
66void comment(int style)
67{
68 int ch , prev=0;
69 if (style == multiline)
70 {
71 while ( (ch = input()) != EOF )
72 {
73 if (prev == '*' && ch == '/')
74 return ;
75
76 prev = ch;
77 }
78
79 return ;
80 }
81 else
82 {
83 while ( (ch = input()) != EOF )
84 {
85 if (ch == '\n')
86 {
87 fprintf(yyout,"%c",'\n');
88 return ;
89 }
90 }
91 }
92}
93int yywrap()
94{
95 return 1;
96}
97
posted on 2009-05-07 14:21
zhaoyg 阅读(645)
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