import java.io.*;

class AtoiDemo
{
   /* -----
	  PutBit(b): prints "1" if b != 0 and "0" otherwise
      ----- */
   private static void PutBit(int b)
    {
      if (b != 0)
         System.out.print("1");
      else
         System.out.print("0");
    }

   /* -----
	  PrintAsciiCode(c): prints an 8 bit quantity in legible "0" and "1"
      ----- */
   private static void PrintAsciiCode(char c)
    {
      int i;

      for (i = 7; i >= 0; i--)
         PutBit(c & (1 << i));
    }

   /* -----
	  PrintIntCode(c): prints a 32 bit quantity in legible "0" and "1"
      ----- */
   private static void PrintIntCode(int k)
    {
      int i;

      for (i = 31; i >= 0; i--)
         PutBit(k & (1 << i));
    }


   /* ---
      atoi(s): Ascii to Integer conversion function
      --- */
   private static int atoi(String s)
    {
      int startpos, sign;
      int value;
      int i;

      System.out.print("  Input string: ");
      for (i = 0; i < s.length(); i++)
         System.out.print("   " + s.charAt(i));
      System.out.println();
      System.out.println();

      /* -------
         Convert string to two's compl. representation
         ------- */
      if (s.charAt(0) == '-')
       { sign = -1;
         startpos = 1;
       }
      else
       { sign = 1;
         startpos = 0;
       }

      System.out.println("  sign = " + sign);

      value = 0;
      for (i = startpos; i < s.length(); i++)
       { 
         System.out.print("  value is now = " + value);
         System.out.print(" (");
         PrintIntCode(value);
         System.out.print(")");
         System.out.println("\tnext digit is " + s.charAt(i));

         value = ((int) s.charAt(i) - (int) '0') + 10*value;
       }
      System.out.print("  value is now = " + value);
      System.out.print(" (");
      PrintIntCode(value);
      System.out.println(") - no more digits !");
      System.out.println();

      System.out.println("  Incorporating sign...");
      System.out.print("  Before: "); 
      PrintIntCode(value);
      System.out.println();

      if (sign == -1)
         value = -value;
      System.out.print("  After:  "); 
      PrintIntCode(value);
      System.out.println();

      System.out.print("  Final value is = " + value);
      System.out.println();
      return(value);
    }

   public static void main(String[] args) throws IOException
    {
      BufferedReader stdin = new BufferedReader
				   (new InputStreamReader(System.in));
      String s;
      int value;
      int i;

      System.out.println("Program reads a char string and converts "+
		   "it to int representation");
      System.out.println();

      while (true)
       {
         System.out.println();
         System.out.print("Enter a number: ");

				// Ordinarily, one would use:
				//   i = Integer.parseInt (stdin.readLine());
				// Java will do the conversion for us...
				// We are here to reveil to you what is
				// going on inside Integer.parseInt()

         s = stdin.readLine();

         // ******************************
         // Show the characters entered
         // ******************************
         System.out.println("What you have actually entered are:\n");
         System.out.print("\t");
         for (i = 0; i < s.length(); i++)
          { PrintAsciiCode(s.charAt(i));
            System.out.print(" (" + (int) s.charAt(i));
            System.out.print(") ");
          }
         System.out.println("\n");

         // **********************************************
         // Show ASCII codes for the characters entered
         // **********************************************
         System.out.print("These are the ASCII codes for char: ");
         for (i = 0; i < s.length(); i++)
          { System.out.print(" " + s.charAt(i));
          } 
         System.out.print("\n\n");

         // **********************************************
         // Now convert !
         // **********************************************
         System.out.print("Now converting ASCII codes to "+
			  "2's complement representation..\n");

         value = atoi(s);

         System.out.print("\nTwo's complement representation is: ");
         PrintIntCode(value); System.out.print("\n");
         System.out.println("Decimal value = " + value);
       }
    }
}