BinaryToHexadecimal.java

import java.util.*;
/**
 * Converts any Binary Number to a Hexadecimal Number
 * 
 * @author Nishita Aggarwal
 *
 */
public class BinaryToHexadecimal {
   
	/**
	 * This method converts a binary number to
	 * a hexadecimal number.
	 * 
	 * @param binary The binary number
	 * @return The hexadecimal number
	 */ 
	static String binToHex(int binary)
	{
		//hm to store hexadecimal codes for binary numbers within the range: 0000 to 1111 i.e. for decimal numbers 0 to 15
		HashMap<Integer,String> hm=new HashMap<>();	
		//String to store hexadecimal code
		String hex="";
		int i;
		for(i=0 ; i<10 ; i++)
		{
			hm.put(i, String.valueOf(i));
		}
		for(i=10 ; i<16 ; i++)	hm.put(i,String.valueOf((char)('A'+i-10)));
		int currbit;
		while(binary != 0)
		{
			int code4 = 0;	//to store decimal equivalent of number formed by 4 decimal digits
			for(i=0 ; i<4 ; i++)
			{
				currbit = binary % 10;
				binary = binary / 10;
				code4 += currbit * Math.pow(2, i);
			}
			hex= hm.get(code4) + hex;
		}
		return hex; 
	}
	
	/**
	 * Main method
	 * 
	 * @param args Command line arguments
	 */
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("Enter binary number:");
		int binary = sc.nextInt();
		String hex = binToHex(binary);
		System.out.println("Hexadecimal Code:" + hex);
		sc.close();
	}
}