Java Exercises: Convert a hexadecimal to a binary number

Java Basic: Exercise-29 with Solution

Write a Java program to convert a hexadecimal to a binary number.

Hexadecimal number: This is a positional numeral system with a radix, or base, of 16. Hexadecimal uses sixteen distinct symbols, most often the symbols 0-9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a, b, c, d, e, f) to represent values ten to fifteen.

Binary number: A binary number is a number expressed in the base-2 numeral system or binary numeral system. This system uses only two symbols: typically 1 (one) and 0 (zero).

Test Data:
Input any hexadecimal number: 37

Pictorial Presentation: Hexadecimal to Binary number

Sample Solution:

Java Code:

import java.util.Scanner;
public class Exercise29 {
     public static int hex_to_decimal(String s)
    {
             String digits = "0123456789ABCDEF";
             s = s.toUpperCase();
             int val = 0;
             for (int i = 0; i < s.length(); i++)
             {
                 char c = s.charAt(i);
                 int d = digits.indexOf(c);
                 val = 16*val + d;
             }
             return val;
    }
    public static void main(String args[])
    {
        String hexdec_num;
        int dec_num, i=1, j;
        int bin_num[] = new int[100];
        Scanner scan = new Scanner(System.in);
		
        System.out.print("Enter Hexadecimal Number : ");
        hexdec_num = scan.nextLine();
        
        /* convert hexadecimal to decimal */        
        dec_num = hex_to_decimal(hexdec_num);
        
        /* convert decimal to binary */        
        while(dec_num != 0)
        {
            bin_num[i++] = dec_num%2;
            dec_num = dec_num/2;
        }
		
        System.out.print("Equivalent Binary Number is: ");
        for(j=i-1; j>0; j--)
        {
            System.out.print(bin_num[j]);
        }
        System.out.print("\n");
    }
}

Sample Output:

Enter Hexadecimal Number : 37                                                                                 
Equivalent Binary Number is: 110111

Flowchart:

Java Code Editor:

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