/* Base Conversion Program (bcp)

   File: bcp.java
 Author: Algorithm designed by David Cronin in 1982
Version: 2009-Feb-01

Compiling:

javac bcp.java

NOTE: If you get the error 	   Error: Could not find or load main class...
      Do the following...
	  1. Find a JDK version  (java -version)
	  2. Modify the path point to the correct java.
	     ie. set PATH="C:\Program Files (x86)\Java\jdk1.8.0_121\bin";%PATH%

Execute the compiled banner.class file.	NOTE: The banner.class can run under a jre.

To run: java -cp . bcp [number] [oldbase] [newbase]

*/
import java.io.*;

public class bcp {
 public static void main (String args[]) {
  String sBaseNumbers = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  String sDigit="";
  String sConvertedNumber="";
  String sMYNUM="";
  int iDigits;
  int iModPtr;
  int iBaseNumberPtr = 0;
  int iACTUAL = 0;
  int iOldBase;
  int iNewBase;
  double dToDecimal = 0;

  if ( args.length != 3 ) {
   System.out.print(" Number: "); sMYNUM=readLine();
   System.out.print("OldBase: "); iOldBase=Integer.parseInt(readLine());
   System.out.print("NewBase: "); iNewBase=Integer.parseInt(readLine());
  } else {
   sMYNUM = args [0];
   iOldBase = Integer.parseInt(args [1]);
   iNewBase = Integer.parseInt(args [2]);
  }

  sMYNUM = sMYNUM.toUpperCase();

  iDigits=sMYNUM.length();

/* Convert the number supplied to decimal. Base-10 */
  while ( iDigits > 0 ) {
   sDigit = sMYNUM.substring(iDigits-1,iDigits);
   iBaseNumberPtr = sBaseNumbers.indexOf(sDigit);
   dToDecimal += (double)iBaseNumberPtr * Math.pow((double)iOldBase,(double)(sMYNUM.length()-iDigits));
   iDigits--;
   if ( iBaseNumberPtr > iACTUAL ) { iACTUAL = iBaseNumberPtr; }
  }

/* Optional error trapping */
  if ( iACTUAL > iOldBase ) {
   dToDecimal=0; iACTUAL++;
   sConvertedNumber = sMYNUM + " is not base " + Integer.toString(iOldBase) + ", however, is a " +
                      Integer.toString(iACTUAL) + " base number.";
  }
  if ( iOldBase > sBaseNumbers.length() || iOldBase < 2 ) {
   dToDecimal = 0;
   sConvertedNumber += "\nOldBase outside the range of 2 to " + Integer.toString(sBaseNumbers.length()) + ".";
  }
  if ( iNewBase > sBaseNumbers.length() || iNewBase < 2 ) {
   dToDecimal = 0;
   sConvertedNumber += "\nNewBase outside the range of 2 to " + Integer.toString(sBaseNumbers.length()) + ".";
  }
/* End of optional error trapping */

/* Convert the decimal to the new base */
  while ( (int)dToDecimal > 0 ) {
   iModPtr = (int)(dToDecimal % (double)iNewBase);
   sConvertedNumber = sBaseNumbers.substring(iModPtr,iModPtr+1) + sConvertedNumber;
   dToDecimal = dToDecimal / (double)iNewBase ;
  }

/* Present the number in its new base */
  System.out.print(sConvertedNumber);
 }


 public static String readLine()
 {
  String s = "";
  try {
   InputStreamReader converter = new InputStreamReader(System.in);
   BufferedReader in = new BufferedReader(converter);
   s = in.readLine();
  } catch (Exception e) {
   System.out.println("Error! Exception: "+e);
  }
  return s;
 }
}