Binary representation of a given number

Write a program to print Binary representation of a given number. 

Source: Microsoft Interview Set-3

Method 1: Iterative
For any number, we can check whether its ‘i’th bit is 0(OFF) or 1(ON) by bitwise ANDing it with “2^i” (2 raise to i). 

1) Let us take number 'NUM' and we want to check whether it's 0th bit is ON or OFF    
    bit = 2 ^ 0 (0th bit)
    if  NUM & bit >= 1 means 0th bit is ON else 0th bit is OFF

2) Similarly if we want to check whether 5th bit is ON or OFF    
    bit = 2 ^ 5 (5th bit)
    if NUM & bit >= 1 means its 5th bit is ON else 5th bit is OFF.

Let us take unsigned integer (32 bit), which consist of 0-31 bits. To print binary representation of unsigned integer, start from 31th bit, check whether 31th bit is ON or OFF, if it is ON print “1” else print “0”. Now check whether 30th bit is ON or OFF, if it is ON print “1” else print “0”, do this for all bits from 31 to 0, finally we will get binary representation of number.

C++

// C++ Program for the binary
// representation of a given number
#include <bits/stdc++.h>
using namespace std;

  void bin(long n)
  {
    long i;
    cout << "0";
    for (i = 1 << 30; i > 0; i = i / 2)
    {
      if((n & i) != 0)
      {
        cout << "1";
      }
      else
      {
        cout << "0";
      }
    }
  }

// Driver Code
int main(void)
{
    bin(7);
    cout << endl;
    bin(4);
}

// This code is contributed by souravghosh0416

C

#include<stdio.h>
void bin(unsigned n)
{
    unsigned i;
    for (i = 1 << 31; i > 0; i = i / 2)
        (n & i) ? printf("1") : printf("0");
}

int main(void)
{
    bin(7);
    printf("\n");
    bin(4);
}

Java

public class GFG
{
  static void bin(long n)
  {
    long i;
    System.out.print("0");
    for (i = 1 << 30; i > 0; i = i / 2)
    {
      if((n & i) != 0)
      {
        System.out.print("1");
      }
      else
      {
        System.out.print("0");
      }
    }
  }

  // Driver code
  public static void main(String[] args)
  {
    bin(7);
    System.out.println();
    bin(4);
  }
}

// This code is contributed by divyesh072019.

Python3

def bin(n) :

    i = 1 << 31
    while(i > 0) :

        if((n & i) != 0) :

            print("1", end = "")

        else :
            print("0", end = "")

        i = i // 2

bin(7)
print()
bin(4)

# This code is contributed by divyeshrabadiya07.

C#

using System;

public class GFG{
    static void bin(long n)
    {
        long i;
        Console.Write("0");
        for (i = 1 << 30; i > 0; i = i / 2)
        {
            if((n & i) != 0)
            {
                Console.Write("1");
            }
            else
            {
                Console.Write("0");
            }
        }
    }
    // Driver code
    static public void Main (){
        bin(7);
        Console.WriteLine();
        bin(4);
    }
}
// This code is contributed by avanitrachhadiya2155

Javascript

<script>
// JavaScript Program for the binary
// representation of a given number
    function bin(n)
    {
        let i;
        document.write("0");
        for (i = 1 << 30; i > 0; i = Math.floor(i/2))
        {
            if((n & i) != 0)
            {
                document.write("1");
            }
            else
            {
                document.write("0");
            }
        }
    }

    bin(7);
    document.write("<br>");
    bin(4);


    // This code is contributed by rag2127

</script>

Output

00000000000000000000000000000111
00000000000000000000000000000100

Method 2: Recursive
Following is recursive method to print binary representation of ‘NUM’. 

step 1) if NUM > 1
    a) push NUM on stack
    b) recursively call function with 'NUM / 2'
step 2)
    a) pop NUM from stack, divide it by 2 and print it's remainder.

C++

// C++ Program for the binary
// representation of a given number
#include <bits/stdc++.h>
using namespace std;

void bin(unsigned n)
{
    /* step 1 */
    if (n > 1)
        bin(n / 2);

    /* step 2 */
    cout << n % 2;
}

// Driver Code
int main(void)
{
    bin(7);
    cout << endl;
    bin(4);
}

// This code is contributed
// by Akanksha Rai

C

// C Program for the binary
// representation of a given number
void bin(unsigned n)
{
    /* step 1 */
    if (n > 1)
        bin(n / 2);

    /* step 2 */
    printf("%d", n % 2);
}

// Driver Code
int main(void)
{
    bin(7);
    printf("\n");
    bin(4);
}

Java

// Java Program for the binary
// representation of a given number
class GFG {
    static void bin(int n)
    {
        /* step 1 */
        if (n > 1)
            bin(n / 2);

        /* step 2 */
        System.out.print(n % 2);
    }

    // Driver code
    public static void main(String[] args)
    {
        bin(7);
        System.out.println();
        bin(4);
    }
}

// This code is contributed
// by ChitraNayal

Python3

# Python3 Program for the binary
# representation of a given number


def bin(n):

    if n > 1:
        bin(n//2)

    print(n % 2, end="")


# Driver Code
if __name__ == "__main__":

    bin(7)
    print()
    bin(4)

# This code is contributed by ANKITRAI1

C#

// C# Program for the binary
// representation of a given number
using System;

class GFG {

    static void bin(int n)
    {

        // step 1
        if (n > 1)
            bin(n / 2);

        // step 2
        Console.Write(n % 2);
    }

    // Driver code
    static public void Main()
    {
        bin(7);
        Console.WriteLine();
        bin(4);
    }
}

// This code is contributed ajit

PHP

<?php
// PHP Program for the binary
// representation of a given number
function bin($n)
{
    /* step 1 */
    if ($n > 1)
        bin($n/2);

    /* step 2 */
    echo ($n % 2);
}

// Driver code
bin(7);
echo ("\n");
bin(4);

// This code is contributed
// by Shivi_Aggarwal
?>

Javascript

<script>

// Javascript program for the binary
// representation of a given number
function bin(n)
{

    // Step 1
    if (n > 1)
        bin(parseInt(n / 2, 10));

    // Step 2
    document.write(n % 2);
}

// Driver code
bin(7);
document.write("</br>");
bin(4);

// This code is contributed by divyeshrabadiya07

</script>

Output

111
100

Method 3: Recursive using bitwise operator
Steps to convert decimal number to its binary representation are given below: 

step 1: Check n > 0
step 2: Right shift the number by 1 bit and recursive function call
step 3: Print the bits of number

C++

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;

// Function to convert decimal
// to binary number
void bin(unsigned n)
{
    if (n > 1)
        bin(n >> 1);

    printf("%d", n & 1);
}

// Driver code
int main(void)
{
    bin(131);
    printf("\n");
    bin(3);
    return 0;
}

Java

// Java implementation of the approach

class GFG {

    // Function to convert decimal
    // to binary number
    static void bin(Integer n)
    {
        if (n > 1)
            bin(n >> 1);

        System.out.printf("%d", n & 1);
    }

    // Driver code
    public static void main(String[] args)
    {
        bin(131);
        System.out.printf("\n");
        bin(3);
    }
}
/*This code is contributed by PrinciRaj1992*/

Python3

# Python 3 implementation of above approach

# Function to convert decimal to
# binary number


def bin(n):

    if (n > 1):
        bin(n >> 1)
    print(n & 1, end="")


# Driver code
bin(131)
print()
bin(3)

# This code is contributed by PrinciRaj1992

C#

// C# implementation of above approach
using System;

public class GFG {

    // Function to convert decimal
    // to binary number
    static void bin(int n)
    {
        if (n > 1)
            bin(n >> 1);

        Console.Write(n & 1);
    }

    // Driver code
    public static void Main()
    {
        bin(131);
        Console.WriteLine();
        bin(3);
    }
}
/*This code is contributed by PrinciRaj1992*/

PHP

<?php
// PHP implementation of the approach

// Function to convert decimal
// to binary number
function bin($n)
{
    if ($n > 1)
    bin($n>>1);

    echo ($n & 1);
}

// Driver code
bin(131);
echo "\n";
bin(3);

// This code is contributed
// by Akanksha Rai

Javascript

<script>
// JavaScript implementation of the approach

// Function to convert decimal
// to binary number
function bin(n)
{
    if (n > 1)
        bin(n >> 1);

    document.write(n & 1);
}

// Driver code

    bin(131);
    document.write("<br>");
    bin(3);


// This code is contributed by Surbhi Tyagi.

</script>

Output

10000011
11

Method 4: Using Bitset of C++

We can use the bitset class of C++ to store the binary representation of any number (positive as well as a negative number). It offers us the flexibility to have the number of bits of our desire, like whether we want to have 32-bit binary representation of just an 8-bit representation of a number.

A complete guide to using bitset can be found on this gfg article LINK.

C++

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

int main()
{

    int n = 5, m = -5;
    bitset<8> b(n);
    bitset<8> b1(m);
    cout << "Binary of 5:" << b << endl;
    cout << "Binary of -5:" << b1 << endl;
    return 0;
}

Output:
Binary of 5:00000101
Binary of -5:11111011

Method 5: Using Inbuilt library:

C++

// C++ program for the above approach

#include <bits/stdc++.h>

using namespace std;

void binary(int num){
      //converts the number to binary
      //and removes leading zeroes
     cout << bitset<32>(num).to_string().substr(32 - log2(num));
}

// Driver Code
int main()
{
    int x = 10;
    binary(x);

}


// This code is contributed phasing17

Java

// Java program for the above approach

import java.util.*;

class GFG {

static void binary(int num){

    System.out.println("the binary number is : "+ Integer.toString(num,2));

}

// Driver Code
public static void main(String[] args)
{
    int x = 10;
    binary(x);

}
}

// This code is contributed by sanjoy_62.

Python3

def binary(num):
    return int(bin(num).split('0b')[1])

if __name__ == "__main__" :
    x = 10
    binary_x = binary(x)
    print("the binary number is :",binary_x)

# This code is contributed by Rishika Gupta.

C#

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

static void binary(int num){

    Console.WriteLine("the binary number is : "+ Convert.ToString(num,2));

}

// Driver Code
public static void Main(String[] args)
{
    int x = 10;
    binary(x);
}
}

// This code is contributed by code_hunt.

Javascript

// JavaScript code for the above approach
const number = 10;

const Binary_Number = number.toString(2);

console.log("the binary number is : "+ Binary_Number);

// This code is contribute by sam

Output:

the binary number is : 1010

Time Complexity: O(1)
Auxiliary Space: O(1)
Video tutorial

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This article is compiled by Narendra Kangralkar.