JavaAlgorithms/Conversions/BinaryToHexadecimal.java

package Conversions;

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();
  }
}