Convert a given Decimal number to its BCD representation

Given a decimal number N, the task is to convert N to it’s Binary Coded Decimal(BCD) form.
Examples:

Input: N = 12 
Output: 0001 0000 
Explanation:
Considering 4-bit concept: 
1 in binary is 0001 and 2 in binary is 0010. 
So it’s equivalent BCD is 0001 0010.

Input: N = 10 
Output: 0001 0000 
Explanation:
Considering 4-bit concept: 
1 in binary is 0001 and 0 in binary is 0000. 
So it’s equivalent BCD is 0001 0000. 

Approach:

1. Reverse the digits of the given number N using the approach discussed in this article and stored the number in Rev.
2. Extract the digits of Rev and print the Binary form of the digit using bitset.
3. Repeat the above steps for each digit in Rev.

Below is the implementation of the above approach:

C++

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;

// Function to convert Decimal to BCD
void BCDConversion(int n)
{
    // Base Case
    if (n == 0) {
        cout << "0000";
        return;
    }

    // To store the reverse of n
    int rev = 0;

    // Reversing the digits
    while (n > 0) {
        rev = rev * 10 + (n % 10);
        n /= 10;
    }

    // Iterate through all digits in rev
    while (rev > 0) {

        // Find Binary for each digit
        // using bitset
        bitset<4> b(rev % 10);

        // Print the Binary conversion
        // for current digit
        cout << b << ' ';

        // Divide rev by 10 for next digit
        rev /= 10;
    }
}

// Driver Code
int main()
{
    // Given Number
    int N = 12;

    // Function Call
    BCDConversion(N);
    return 0;
}

Java

// Java program for the above approach
import java.util.*;

class Gfg
{

    // Function to convert Decimal to BCD
    public static void BCDConversion(int n)
    {

        // Base Case
        if(n == 0)
        {
            System.out.print("0000");
        }

        // To store the reverse of n
        int rev = 0;

        // Reversing the digits
        while (n > 0)
        {
            rev = rev * 10 + (n % 10);
            n /= 10;
        }

        // Iterate through all digits in rev
        while(rev > 0)
        {

            // Find Binary for each digit
            // using bitset
            String b = Integer.toBinaryString(rev % 10);

            b = String.format("%04d", Integer.parseInt(b));

              // Print the Binary conversion
            // for current digit
            System.out.print(b + " ");

            // Divide rev by 10 for next digit
            rev /= 10;
        }
    }

  // Driver code
  public static void main(String []args)
  {

    // Given Number
    int N = 12;

    // Function Call
    BCDConversion(N);
  }
}

// This code is contributed by avanitrachhadiya2155

Python3

# Python3 program for the above approach

# Function to convert Decimal to BCD
def BCDConversion(n) :

    # Base Case
    if (n == 0) :
        print("0000")
        return

    # To store the reverse of n
    rev = 0

    # Reversing the digits
    while (n > 0) :
        rev = rev * 10 + (n % 10)
        n = n // 10

    # Iterate through all digits in rev
    while (rev > 0) :

        # Find Binary for each digit
        # using bitset
        b = str(rev % 10)

        # Print the Binary conversion
        # for current digit
        print("{0:04b}".format(int(b, 16)), end = " ")

        # Divide rev by 10 for next digit
        rev = rev // 10

# Given Number
N = 12

# Function Call
BCDConversion(N)

# This code is contributed by divyeshrabadiya07

C#

// C# program for the above approach
using System;
using System.Collections.Generic;
class GFG {

    // Function to convert Decimal to BCD
    static void BCDConversion(int n)
    {
        // Base Case
        if (n == 0) {
            Console.Write("0000");
            return;
        }

        // To store the reverse of n
        int rev = 0;

        // Reversing the digits
        while (n > 0) {
            rev = rev * 10 + (n % 10);
            n /= 10;
        }

        // Iterate through all digits in rev
        while (rev > 0) {

            // Find Binary for each digit
            // using bitset
            string b = Convert.ToString(rev % 10, 2).PadLeft(4, '0');

            // Print the Binary conversion
            // for current digit
            Console.Write(b + " ");

            // Divide rev by 10 for next digit
            rev /= 10;
        }
    }

  static void Main() {

    // Given Number
    int N = 12;

    // Function Call
    BCDConversion(N);
  }
}

// This code is contributed divyesh072019

Javascript

<script>

    //JavaScript for the above approach

    // Function to convert Decimal to BCD
    function BCDConversion(n)
    {
        // Base Case
        if (n == 0) {
            document.write("0000");
            return;
        }

        // To store the reverse of n
        let rev = 0;

        // Reversing the digits
        while (n > 0) {
            rev = rev * 10 + (n % 10);
            n = parseInt(n / 10, 10);
        }

        // Iterate through all digits in rev
        while (rev > 0) {

            // Find Binary for each digit
            // using bitset
            let b = (rev % 10).toString(2);
            while(b.length != 4)
            {
                b = "0" + b;
            }

            // Print the Binary conversion
            // for current digit
            document.write(b + " ");

            // Divide rev by 10 for next digit
            rev = parseInt(rev / 10, 10);
        }
    }

    // Driver Code
    // Given Number
    let N = 12;

    // Function Call
    BCDConversion(N);

</script>

Output:

0001 0010

Time Complexity: O(log₁₀ N), where N is the given number.
Auxiliary Space: O(1) because constant space has been used