In Computer Science, quite often, we are required to convert numbers from one base to another. Numbers with base 2, 8, 10 and 16 are commonly used.

Base 2 numbers are binary numbers. Base 8 are octal numbers. Base 10 are decimal numbers. Base 16 are hexadecimal numbers.

Write a program in Java to convert a number in any base into another base, limiting the base value up to 16.

Example:
INPUT:
Enter the number: AF
Source base: 16
Destination base: 2
OUTPUT:
10101111

import java.io.*;
class AnyBase{
    public static void main(String args[])throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter the number: ");
        String n = br.readLine();
        n = n.toUpperCase();
        System.out.print("Source base: ");
        int s = Integer.parseInt(br.readLine());
        System.out.print("Destination base: ");
        int d = Integer.parseInt(br.readLine());
        String r = convert(n, s, d);
        System.out.println(r);
    }
    public static String convert(String n, int b1, int b2){
        if(b1 == b2)
            return n;
        int deci = 0;
        if(b1 != 10)
            deci = getDecimal(n, b1);
        String result = "";
        if(deci == 0)
            result = "0";
        while(deci != 0){
            int d = deci % b2;
            if(d < 10) 
                result = d + result;
            else if(d == 10)
                result = 'A' + result;
            else if(d == 11)
                result = 'B' + result;
            else if(d == 12)
                result = 'C' + result;
            else if(d == 13)
                result = 'D' + result;
            else if(d == 14)
                result = 'E' + result;
            else if(d == 15)
                result = 'F' + result;
            deci /= b2;
        }
        return result;
    }
    public static int getDecimal(String n, int base){
        int d = 0;
        int num = 0;
        int p = 0;
        for(int i = n.length() - 1; i >= 0; i--){
            char ch = n.charAt(i);
            switch(ch){
                case '0':
                num = 0;
                break;
                case '1':
                num = 1;
                break;
                case '2':
                num = 2;
                break;
                case '3':
                num = 3;
                break;
                case '4':
                num = 4;
                break;
                case '5':
                num = 5;
                break;
                case '6':
                num = 6;
                break;
                case '7':
                num = 7;
                break;
                case '8':
                num = 8;
                break;
                case '9':
                num = 9;
                break;
                case 'A':
                num = 10;
                break;
                case 'B':
                num = 11;
                break;
                case 'C':
                num = 12;
                break;
                case 'D':
                num = 13;
                break;
                case 'E':
                num = 14;
                break;
                case 'F':
                num = 15;
                break;
            }
            d += num * (int)Math.pow(base, p);
            p++;
        }
        return d;
    }
}