// javac scan.java // compile
// java scan example1.x // run

import java.io.*; // nice way to import everything


public class scan // needs to match the file name as in scan.java
{

  public static void main(String[] args) throws IOException
  {
    token[] identified = new token[999]; // array of identified tokens
    int line = 1; // line number
    int pos = 0; // position on line
    char sym = 0; // symbol as a part of token
    String[] tokens = new String[999]; // array of all tokens
    tokens[0] = "";
    int tokenNum = 0; // number of tokens


    FileReader scanner = new FileReader(args[0]); // Java thing used for input


    while(sym != (char) -1) // scanner.read returns -1 when reaches eof, thus this will read till eof
    {

      token curr = new token();

      pos++;
      sym = (char) scanner.read(); // reads a char, returns it as an int. Thus has to be casted as char


      if(tokenNum > 1 && tokens[tokenNum - 2] == "") // these two blocks are used to delete "empty" tokens caused by spaces, tabs and \n
      {
        tokens[tokenNum - 2] = tokens[tokenNum - 1];
        tokens[tokenNum - 1] = "";
        tokenNum--;
      }
      if(tokenNum > 0 && tokens[tokenNum - 1] == "")
      {
        tokens[tokenNum - 1] = "";
        tokenNum--;
      }


      if(Character.isLetterOrDigit(sym) || sym == '_') { // if token is an Identifier
        tokens[tokenNum] += sym;
        pos++;
      }

      else if (sym == '(' || // if token is an operator
               sym == ')' ||
               sym == '{' ||
               sym == '}' ||
               sym == '+' ||
               sym == '-' ||
               sym == '*' ||
               sym == '/' ||
               sym == '<' ||
               sym == '>' ||
               sym == ';')
      {

        curr.value = tokens[tokenNum]; // takes the current string and store it in curr.value
        curr.pos = pos - tokens[tokenNum].length(); // gets the position of where the current token started
        curr.line = line; // line number

        identified[tokenNum] = curr;
        pos++;

        tokenNum++; // has to be a new token
        tokens[tokenNum] = "";
        tokens[tokenNum] += sym; // stores operator as a token

        curr.value = tokens[tokenNum];
        curr.pos = pos;
        curr.line = line;

        identified[tokenNum] = curr;

        tokenNum++; // all operators are 1 symbol, thus next symbol will be in a different token
        tokens[tokenNum] = "";
      }

      else if (sym == '\n')
      {

        curr.value = tokens[tokenNum];
        curr.pos = pos - tokens[tokenNum].length();
        curr.line = line;

        identified[tokenNum] = curr;

        pos = 0; // reset column position because its a new line
        line++; // increment line count
        tokenNum++;
        tokens[tokenNum] = "";
      } else if (sym == ' ') {

        curr.value = tokens[tokenNum];
        curr.pos = pos - tokens[tokenNum].length();
        curr.line = line;

        identified[tokenNum] = curr;

        pos++; //inc position but not line count
        tokenNum++;
        tokens[tokenNum] = "";
      } else if (sym == '\t') {

        curr.value = tokens[tokenNum];
        curr.pos = pos - tokens[tokenNum].length();
        curr.line = line;

        identified[tokenNum] = curr;

        pos += 2; //increment position count by 2
        tokenNum++;
        tokens[tokenNum] = "";
      }

    } // while

    for(int i = 0; i <= tokenNum; i++) // prints all tokens
    {
      System.out.println(tokens[i]);
      System.out.println(identified[i].value);
    }

  } // main

}