Convert the given BCD to its equivalent Binary form

Given a BCD (Binary Coded Decimal), the task is to convert this to its equivalent Binary number. 

Examples:

Input: 1001000 
Output: 110000 
Explanation:
Integer value of the given BCD is 48(0100 -> 4, 1000 -> 8). 
(48)₁₀ = (110000)₂

Input: 1001001 
Output: 110000

Approach: In order to solve this problem we need to split the given BCD number into binary chunks of length 4 and convert them to integer one by one to generate the final integer representation of the given BCD. Once generated, convert the integer to its binary form.
Below is the implementation of the above approach.

C++

// C++ code to convert BCD to its
// equivalent Binary

#include <bits/stdc++.h>
using namespace std;

// Function to convert BCD to Decimal
string bcdToBinary(string s)
{
    int l = s.length();
    int num = 0;
    int mul = 1;
    int sum = 0;

     // If the length of given BCD is not
    // divisible by 4
    for (int i = l % 4 - 1; i >= 0; i--)
    {
        sum += (s[i] - '0') * mul;
        mul *= 2;
    }
    num = sum;
    sum = 0;
    mul = pow(2, 3);
    int ctr = 0;
    for (int i = l % 4; i < l; i++)
    {
        ctr++;
        sum += (s[i] - '0') * mul;
        mul /= 2;
        if (ctr == 4) {
            num = num * 10 + sum;
            sum = 0;
            mul = pow(2, 3);
            ctr = 0;
        }
    }

    // Convert decimal to binary
    string ans = "";
    while (num > 0) {
        ans += (char)(num % 2 + '0');
        num /= 2;
    }
    reverse(ans.begin(), ans.end());
    return ans;
}

// Driver Code
int main()
{
    string s = "1001000";

    // Function Call
    cout << bcdToBinary(s);
    return 0;
}

Java

// Java code to convert BCD to its
// equivalent Binary
import java.io.*;
import java.util.*;

class GFG{

// Function to convert BCD to Decimal
static String bcdToBinary(String s)
{
    int l = s.length();
    int num = 0;
    int mul = 1;
    int sum = 0;

    // If the length of given BCD is not
    // divisible by 4
    for(int i = l % 4 - 1; i >= 0; i--)
    {
        sum += (s.charAt(i) - '0') * mul;
        mul *= 2;
    }

    num = sum;
    sum = 0;
    mul = (int)Math.pow(2, 3);
    int ctr = 0;

    for(int i = l % 4; i < l; i++)
    {
        ctr++;
        sum += (s.charAt(i) - '0') * mul;
        mul /= 2;

        if (ctr == 4)
        {
            num = num * 10 + sum;
            sum = 0;
            mul = (int)Math.pow(2, 3);
            ctr = 0;
        }
    }

    // Convert decimal to binary
    String ans = "";
    while (num > 0)
    {
        ans += (char)(num % 2 + '0');
        num /= 2;
    }

    StringBuilder ans1 = new StringBuilder();

    // Append a string into StringBuilder input1
    ans1.append(ans);

    // Reverse StringBuilder input1
    ans = ans1.reverse().toString();

    return ans;
}

// Driver code
public static void main(String[] args)
{
    String s = "1001000";

    // Function call
    System.out.println(bcdToBinary(s));
}
}

// This code is contributed by coder001

Python3

# Python3 code to convert
# BCD to its equivalent Binary

# Function to convert
# BCD to Decimal
def bcdToBinary(s):

    l = len(s)
    num = 0;
    mul = 1;
    sum = 0;

    # If the length of given
    # BCD is not divisible by 4
    for i in range(l % 4 - 1,
                   -1, -1):
        sum += (ord(s[i]) -
                ord('0')) * mul;
        mul *= 2;

    num = sum;
    sum = 0;
    mul = pow(2, 3);
    ctr = 0;

    for i in range(l % 4, l):
        ctr += 1;
        sum += (ord(s[i]) -
                ord('0')) * mul;
        mul //= 2;
        if (ctr == 4):
            num = num * 10 + sum;
            sum = 0;
            mul = pow(2, 3);
            ctr = 0;

    # Convert decimal to binary
    ans = "";
    while (num > 0):
        ans += (chr((num % 2) +
                ord('0')));
        num //= 2;
    ans = ans[:: -1]

    return ans;

# Driver code
if __name__ == "__main__":

    s = "1001000";

    # Function Call
    print(bcdToBinary(s));

# This code is contributed by rutvik_56

C#

// C# code to convert BCD to its
// equivalent Binary
using System;
using System.Text;
public class GFG{

// Function to convert BCD to Decimal
static String bcdToBinary(String s)
{
    int l = s.Length;
    int num = 0;
    int mul = 1;
    int sum = 0;

    // If the length of given BCD is not
    // divisible by 4
    for(int i = l % 4 - 1; i >= 0; i--)
    {
        sum += (s[i] - '0') * mul;
        mul *= 2;
    }
    num = sum;
    sum = 0;
    mul = (int)Math.Pow(2, 3);
    int ctr = 0;
    for(int i = l % 4; i < l; i++)
    {
        ctr++;
        sum += (s[i] - '0') * mul;
        mul /= 2;
        if (ctr == 4)
        {
            num = num * 10 + sum;
            sum = 0;
            mul = (int)Math.Pow(2, 3);
            ctr = 0;
        }
    }

    // Convert decimal to binary
    String ans = "";
    while (num > 0)
    {
        ans += (char)(num % 2 + '0');
        num /= 2;
    }
    StringBuilder ans1 = new StringBuilder();

    // Append a string into StringBuilder input1
    ans1.Append(ans);

    // Reverse StringBuilder input1
    ans = reverse(ans1.ToString());
    return ans;
}
static String reverse(String input)
{
        char[] a = input.ToCharArray();
        int l, r = a.Length - 1;
        for (l = 0; l < r; l++, r--)
        {
            char temp = a[l];
            a[l] = a[r];
            a[r] = temp;
        }
        return String.Join("",a);
    }

// Driver code
public static void Main(String[] args)
{
    String s = "1001000";

    // Function call
    Console.WriteLine(bcdToBinary(s));
}
}

// This code is contributed by shikhasingrajput

Javascript

<script>
// Javascript code to convert BCD to its
// equivalent Binary

// Function to convert BCD to Decimal
function bcdToBinary(s)
{
    let l = s.length;
    let num = 0;
    let mul = 1;
    let sum = 0;

    // If the length of given BCD is not
    // divisible by 4
    for (let i = l % 4 - 1; i >= 0; i--)
    {
        sum += (s[i].charCodeAt(0) - '0'.charCodeAt(0)) * mul;
        mul *= 2;
    }
    num = sum;
    sum = 0;
    mul = Math.pow(2, 3);
    let ctr = 0;
    for (let i = l % 4; i < l; i++) {
        ctr++;
        sum += (s[i].charCodeAt(0) - '0'.charCodeAt(0)) * mul;
        mul = Math.floor(mul / 2);
        if (ctr == 4) {
            num = num * 10 + sum;
            sum = 0;
            mul = Math.pow(2, 3);
            ctr = 0;
        }
    }

    // Convert decimal to binary
    let ans = "";
    while (num > 0) {
        ans += String.fromCharCode(num % 2 + '0'.charCodeAt(0));
        num = Math.floor(num / 2);
    }
    ans = ans.split("").reverse().join("")
    console.log(ans)
    return ans;
}

// Driver Code
let s = "1001000";

// Function Call
document.write(bcdToBinary(s));

// This code is contributed by _saurabh_jaiswal
</script>

Output:

110000

Time Complexity: O(N) where N denotes the length of the BCD string provided 
Auxiliary Space: O(1)