Count number of trailing zeros in Binary representation of a number using Bitset

Given a number. The task is to count the number of Trailing Zero in Binary representation of a number using bitset.

Examples:

Input : N = 16
Output : 3
Binary representation of N is 1000. Therefore,
number of zeroes at the end is 3.

Input : N = 8
Output : 2

Approach: We simply set the number in the bitset and then we iterate from 0 index of bitset, as soon as we get 1 we will break the loop because there is no trailing zero after that.



Below is the implementation of above approach:

C++

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// C++ program to count number of trailing zeros
// in Binary representation of a number
// using Bitset
  
#include <bits/stdc++.h>
using namespace std;
  
// Function to count number of trailing zeros in
// Binary representation of a number
// using Bitset
int CountTrailingZeros(int n)
{
    // declare bitset of 64 bits
    bitset<64> bit;
  
    // set bitset with the value
    bit |= n;
  
    int zero = 0;
  
    for (int i = 0; i < 64; i++) {
        if (bit[i] == 0)
            zero++;
        // if '1' comes then break
        else
            break;
    }
  
    return zero;
}
  
// Driver Code
int main()
{
    int n = 4;
  
    int ans = CountTrailingZeros(n);
  
    cout << ans << "\n";
  
    return 0;
}

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Java

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// Java program to count number of trailing zeros
// in Binary representation of a number
// using Bitset
import java.util.*;
import java.lang.*; 
import java.io.*;
  
class GFG
{
       
    // Function to count number of trailing zeros in
    // Binary representation of a number
    // using Bitset
    static int CountTrailingZeros(int n)
    {
          
        String bit = Integer.toBinaryString(n);
        StringBuilder bit1 = new StringBuilder(); 
        bit1.append(bit);
        bit1=bit1.reverse();
        int zero = 0;
       
        for (int i = 0; i < 64; i++) {
            if (bit1.charAt(i) == '0')
                zero++;
            // if '1' comes then break
            else
                break;
        }
       
        return zero;
    }
       
    // Driver Code
    public static void main(String []args)
    {
        int n = 4;
       
        int ans = CountTrailingZeros(n);
       
        System.out.println(ans);
    }
}
  
// This code is contributed by chitranayal

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Python3

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# Python3 program to count 
# number of trailing zeros in 
# Binary representation of a number
  
# Function to count number of 
# trailing zeros in Binary
# representation of a number
def CountTrailingZeros(n):
      
    # declare bitset of 64 bits
    bit = bin(n)[2:]
    bit = bit[::-1]
  
    zero = 0;
  
    for i in range(len(bit)):
        if (bit[i] == '0'):
            zero += 1
              
        # if '1' comes then break
        else:
            break
  
    return zero
  
# Driver Code
n = 4
  
ans = CountTrailingZeros(n)
  
print(ans)
  
# This code is contributed 
# by Mohit Kumar

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Output:

2

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