/* dfa.c - Don Yang (uguu.org)
   Strip C comments using deterministic finite automaton.

   How this works is fairly obvious once you draw out the diagram.
   Each array element in dfa[] is a state, and each word in the string
   are the edges:
      First character in word desinates the character to match (. = any)
      The letters are the actions when a character matches
         s = write space
         e = echo character
         f = write forward slash
      A digit ends an edge definition, and is the next state to go to.

   06/15/01
                                                                           */

#include<ctype.h>
#include<stdio.h>

static char *dfa[] = {
   /* state 0 */ "/1    'e4   \"e6  .e0",
   /* state 1 */ "*ss2  /f1   .fe0",
   /* state 2 */ "*s3   .s2",
   /* state 3 */ "*s3   /s0   .s2",
   /* state 4 */ "'e0   \\e5  .e4",
   /* state 5 */ ".e4",
   /* state 6 */ "\"e0  \\e7  .e6",
   /* state 7 */ ".e6"};
static int state = 0;
static int input;
static char *cursor;


int main(void)
{
   while( (input = getchar()) != EOF )
   {
      /* Find edge with matching character */
      for(cursor = dfa[state]; *cursor; cursor++)
      {
         if( *cursor == ' ' )
            continue;
         if( *cursor == '.' || (int)(*cursor) == input )
            break;
         for(; !isdigit(*cursor); cursor++);
      }

      /* Execute commands */
      for(; !isdigit(*cursor); cursor++)
      {
         if( *cursor == 's' )    putchar(input < ' ' ? input : ' ');
         if( *cursor == 'e' )    putchar(input);
         if( *cursor == 'f' )    putchar('/');
      }

      state = *cursor - '0';
   }

   return 0;
}