c - Extracting comments and strings - edited

Question

This is an edited, corrected, more specific version of a previous question of mine. So I'm doing a homework assignment where we have to use a sliding window to print the comments and strings from an input file coming from the stdin. I am very close but something is missing. Following is my code, an input, my current output, and the correct output. The // comments and ignoring characters work. I'm not exactly sure the problem with strings and in /**/ comments I can't get rid of the the star in the initial /* without screwing up it finding the */. Thank you anyone who can offer assistance.

Code:

#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;
}

Input:

 /* 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**/

My Output:

* 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*

Correct Output:

 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*

Answer 1

Here's how you could do it:

 /* 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;
}

Output of this program on its source code:

<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>