/* Scan.java: scanner implementation.
 * Recognizes C-type comments
 * Based on a finite-state automaton.
 */
import java.io.*;
public class Scan {
   Reader in; // internal file name for input stream
   boolean fileOpen = false; // is the file open yet?
   String fileName; // name of input file, if present

   // Scan(): constructor providing no input file name
   public Scan() {
      fileName = "";
   }

   // Scan(String ): constructor providing input file name
   public Scan(String f) {
      fileName = f;
   }

   // getComment: recognize and return the next comment
   public String getComment()  {
      int state = 0; // state for the finite automaton
      char ch = 0; // single-character buffer
      String s = "/*";
      while (state != 4) {
         if (ch == 65535) { //end-of-file
            System.out.println("Th-th-th-th-that's all folks");
            System.exit(0);
         }
         switch (state) {
         case 0: ch = getNextChar();
              if (ch == '/') state = 1;
              else state = 0; break;
         case 1: ch = getNextChar();
              if (ch == '*') state = 2;
              else state = 0; break;
         case 2: ch = getNextChar();
              s += ch;
              if (ch == '*') state = 3;
              else state = 2; break;
         case 3: ch = getNextChar();
              s += ch;
              if (ch == '*') state = 3;
              else if (ch == '/') state = 4;
              else state = 2; break;
         case 4: return s;
         } // end of switch
      } // end of while
      return s;
   }

   // getNextChar: fetches next char.  Also opens input file
   private char getNextChar() {
      if (!fileOpen) {
         try {
            fileOpen = true;
            if (fileName == "")
               in = new InputStreamReader(System.in);
            else
               in = new FileReader(fileName);
         } catch (IOException e) {
            System.out.println("Exception opening " + fileName);
            System.exit(1);
         }
      }
      char ch = ' '; // keep compiler happy
      try {
         ch = (char)in.read();
      } catch (IOException e) {
         System.out.println("Exception reading character");
         System.exit(1);
      }
      return ch;
   }

}