这是我之前问题的经过编辑,更正,更具体的版本。所以我正在做一个家庭作业,我们必须使用一个滑动窗口来打印来自stdin的输入文件中的注释和字符串。我很亲密,但缺少一些东西。以下是我的代码,输入,我当前的输出和正确的输出。 //
注释和忽略字符有效。我不完全确定字符串的问题,在/ ** / comments中我无法摆脱最初/*
中的星号,而不会搞砸它找到*/
。谢谢任何可以提供帮助的人。
代码:
#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;
}
输入:
/* recognize '...' otherwise see " as start of string: */
int c='\"', d='\'', e = '\012'; // comment line 3
/* recognize "..." otherwise see comments here: */
char s[] = "abc/*not a comment*/efg\"ZZ\'";
char t[] = "ABC//not a comment//EFG\x012\/\/";
char *p = ""; //
int d = '/*'; // comment line 13
/*/*/
/**/
/*Z*/
/***/
/****/
/**A**/
我的输出:
* 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//EFG\x012\/\/""
comment line 13
*
*Z
**
***
**A*
正确输出:
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//EFG\x012\/\/
comment line 13
/
Z
*
**
*A*
答案 0 :(得分:2)
以下是你如何做到的:
/* recognize '...' otherwise see " as start of string: */
int c='\"', d='\'', e = '\012'; // comment line 3
/* recognize "..." otherwise see comments here: */
char s[] = "abc/*not a comment*/efg\"ZZ\'";
char t[] = "ABC//not a comment//EFG\x012\/\/";
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;
}
此程序的源代码输出:
<C comment>
recognize '...' otherwise see " as start of string:
</C comment>
<Char literal>
\"
</Char literal>
<Char literal>
\'
</Char literal>
<Char literal>
\012
</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//EFG\x012\/\/
</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>