这是我之前一个问题的编辑、更正、更具体的版本。我正在做一个家庭作业，我们必须使用滑动窗口来打印来自标准输入文件的注释和字符串。我已经很接近了，但还是少了点什么。下面是我的代码、输入、当前输出和正确的输出。//注释和忽略字符可以工作。我不确定字符串的问题，在/**/注释中，我不能在没有搞砸它找到*/的情况下摆脱初始/*中的星星。感谢任何能提供帮助的人。
#include <stdio.h>
typedef enum
{
Initial,
Comment,
String,
Char,
CPPComment
} extrema;
int main()
{
int c, c1 = 0, c2 = 0;
extrema state = Initial;
extrema next = Initial;
while(1)
{
switch(state)
{
case Initial: next = ((c2 == '*' && c1 == '/') ? Comment : (c2 == '"') ? String : (c2 == '/' && c1 == '/') ? Char : (c2 == ''') ? CPPComment : Initial); break;
case Comment: next = ((c2 == '/' && c1 == '*') ? Initial : Comment); break;
case String: next = ((c2 == '"' && c1 != '\') ? Initial : String); break;
case Char: next = ((c2 == 'n') ? Initial : Char); break;
case CPPComment: next = ((c2 == ''' && c1 != '\') ? Initial : CPPComment); break;
default: next = state;
}
if(state == Comment)
{
if(c1 == '*')
{
if(c2 != '/')
putchar(c1);
else
putchar('n');
}
else
putchar(c1);
}
else if(state == String)
{
if(c2 != '"' || (c2 == '"' && c1 != '\'))
putchar(c2);
}
else if(state == CPPComment)
{
putchar(c2);
}
c = getchar(); if( c < 0) break;
c1 = c2; c2 = c; // slide window
//printf("%i",state);
state = next;
// c2 is the current input byte and c1 is the previous input byte
}
return 0;
}
/* recognize '...' otherwise see " as start of string: */
int c='"', d=''', e = ' 12'; // comment line 3
/* recognize "..." otherwise see comments here: */
char s[] = "abc/*not a comment*/efg"ZZ'";
char t[] = "ABC//not a comment//EFGx012//";
char *p = ""; //
int d = '/*'; // comment line 13
/*/*/
/**/
/*Z*/
/***/
/****/
/**A**/
* recognize '...' otherwise see " as start of string:
comment line 3
* recognize "..." otherwise see comments here:
abc/*not a comment*/efgZZ'"ABC//not a comment//EFGx012//""
comment line 13
*
*Z
**
***
**A*
正确的输出:
recognize '...' otherwise see " as start of string:
comment line 3
recognize "..." otherwise see comments here:
abc/*not a comment*/efg"ZZ'
ABC//not a comment//EFGx012//
comment line 13
/
Z
*
**
*A*
你可以这样做:
/* recognize '...' otherwise see " as start of string: */
int c='"', d=''', e = ' 12'; // comment line 3
/* recognize "..." otherwise see comments here: */
char s[] = "abc/*not a comment*/efg"ZZ'";
char t[] = "ABC//not a comment//EFGx012//";
char *p = ""; //
int dd = '/*'; // comment line 13
/*/*/
/**/
/*Z*/
/***/
/****/
/**A**/
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char** argv)
{
FILE* f;
if (argc == 2 && (f = fopen(argv[1], "rt")) != NULL)
{
int c[2];
enum {
INITIAL,
CCOMMENT1,
CCOMMENT2,
CCOMMENT3,
CPPCOMMENT1,
CPPCOMMENT2,
STRING1,
STRING2,
CHAR1,
CHAR2,
} state = INITIAL;
if ((c[0] = fgetc(f)) == EOF)
return 0;
while ((c[1] = fgetc(f)) != EOF)
{
switch (state)
{
case INITIAL:
if (c[0] == '/' && c[1] == '*')
state = CCOMMENT1, printf("<C comment>n");
else if (c[0] == '/' && c[1] == '/')
state = CPPCOMMENT1, printf("<C++ comment>n");
else if (c[0] == '"')
state = STRING1, printf("<String literal>n");
else if (c[0] == ''')
state = CHAR1, printf("<Char literal>n");
break;
case CCOMMENT1:
case CPPCOMMENT1:
/* skip * in /* and 2nd / in // */
state++;
break;
case CCOMMENT2:
if (c[0] == '*' && c[1] == '/')
state++, printf("n</C comment>n");
else
printf("%c", c[0]);
break;
case CCOMMENT3:
// skip / in */
state = INITIAL;
break;
case CPPCOMMENT2:
if (c[0] == 'n')
state = INITIAL, printf("n</C++ comment>n");
else
printf("%c", c[0]);
break;
case STRING1:
if (c[0] == '"')
state = INITIAL, printf("n</String literal>n");
else if (c[0] == '\')
state = STRING2, printf("%c", c[0]);
else
printf("%c", c[0]);
break;
case STRING2:
// skip escaped character
state = STRING1, printf("%c", c[0]);
break;
case CHAR1:
if (c[0] == ''')
state = INITIAL, printf("n</Char literal>n");
else if (c[0] == '\')
state = CHAR2, printf("%c", c[0]);
else
printf("%c", c[0]);
break;
case CHAR2:
// skip escaped character
state = CHAR1, printf("%c", c[0]);
break;
}
c[0] = c[1];
}
fclose(f);
}
return 0;
}
程序的源代码输出:
<C comment>
recognize '...' otherwise see " as start of string:
</C comment>
<Char literal>
"
</Char literal>
<Char literal>
'
</Char literal>
<Char literal>
12
</Char literal>
<C++ comment>
comment line 3
</C++ comment>
<C comment>
recognize "..." otherwise see comments here:
</C comment>
<String literal>
abc/*not a comment*/efg"ZZ'
</String literal>
<String literal>
ABC//not a comment//EFGx012//
</String literal>
<String literal>
</String literal>
<C++ comment>
</C++ comment>
<Char literal>
/*
</Char literal>
<C++ comment>
comment line 13
</C++ comment>
<C comment>
/
</C comment>
<C comment>
</C comment>
<C comment>
Z
</C comment>
<C comment>
*
</C comment>
<C comment>
**
</C comment>
<C comment>
*A*
</C comment>
<String literal>
rt
</String literal>
<Char literal>
/
</Char literal>
<Char literal>
*
</Char literal>
<String literal>
<C comment>n
</String literal>
<Char literal>
/
</Char literal>
<Char literal>
/
</Char literal>
<String literal>
<C++ comment>n
</String literal>
<Char literal>
"
</Char literal>
<String literal>
<String literal>n
</String literal>
<Char literal>
'
</Char literal>
<String literal>
<Char literal>n
</String literal>
<C comment>
skip * in /* and 2nd / in //
</C comment>
<Char literal>
*
</Char literal>
<Char literal>
/
</Char literal>
<String literal>
n</C comment>n
</String literal>
<String literal>
%c
</String literal>
<C++ comment>
skip / in */
</C++ comment>
<Char literal>
n
</Char literal>
<String literal>
n</C++ comment>n
</String literal>
<String literal>
%c
</String literal>
<Char literal>
"
</Char literal>
<String literal>
n</String literal>n
</String literal>
<Char literal>
\
</Char literal>
<String literal>
%c
</String literal>
<String literal>
%c
</String literal>
<C++ comment>
skip escaped character
</C++ comment>
<String literal>
%c
</String literal>
<Char literal>
'
</Char literal>
<String literal>
n</Char literal>n
</String literal>
<Char literal>
\
</Char literal>
<String literal>
%c
</String literal>
<String literal>
%c
</String literal>
<C++ comment>
skip escaped character
</C++ comment>
<String literal>
%c
</String literal>