import java.io.*;
public class NumberConverter{
	
	public NumberConverter(){
		
	}
	
	
	public static void main(String[] args){
		NumberConverter converter = new NumberConverter();
		boolean done = false;
		while (!done){
			String selection = converter.getSelection();
			selection = selection.trim().toUpperCase();
			char c = selection.charAt(0);
			if (c == 'B'){
				String numberString = converter.getEntry("Enter a Signed Binary Integer");
				byte n = (byte)Integer.parseInt(numberString, 2);
				String hexString = Integer.toHexString(Integer.parseInt(numberString, 2)).toUpperCase();
				while (hexString.length() < 2){
					hexString = "0" + hexString;
				}
				System.out.println(numberString  
					+ " is " + String.valueOf(n) + " decimal or " 
					+ hexString + " hexadecimal.");
			}else if (c == 'D'){
				String numberString = converter.getEntry("Enter a Decimal Integer between -128 and 127");
				int n = Integer.parseInt(numberString);
				String binaryString = Integer.toBinaryString(n);
				while (binaryString.length() < 8){
					binaryString = "0" + binaryString;
				}
				String hexString = Integer.toHexString(n).toUpperCase();
				while (hexString.length() < 2){
					hexString = "0" + hexString;
				}
				System.out.println(numberString
					+ " decimal is " + binaryString + " binary or "
					+ hexString  + " hexadecimal.");
			}else if (c == 'X'){
				done = true;
			}else{
				System.out.println("Unknown Option: Try again.");				
			}
		}
	}
	
	public String getSelection(){
		String menu = "Select one of the following:\n" 
			+ "\n"
			+ "B Convert from Binary to Decimal and Hexadecimal\n"
			+ "D Convert from Decimal to Binary and Hexadecimal\n"
			+ "X Exit\n";
		System.out.println(menu);		
		String userInput = "";
		try{
			InputStreamReader isr = new InputStreamReader(System.in);
			BufferedReader br = new BufferedReader(isr);
			userInput = br.readLine();
		}catch(IOException ioe){
			System.err.println("IOException: " + ioe.getMessage());
		}
		return userInput;
	}

	public String getEntry(String message){
		System.out.println("\n" + message);		
		String userInput = "";
		try{
			InputStreamReader isr = new InputStreamReader(System.in);
			BufferedReader br = new BufferedReader(isr);
			userInput = br.readLine();
		}catch(IOException ioe){
			System.err.println("IOException: " + ioe.getMessage());
		}
		return userInput;
	}
}