What is the output of the following code snippet? C++ #include <iostream> using namespace std; void fun(int& num, int k) { num &= (~(1 << k)); } int main() { int num = 7; int k = 1; fun(num, k); cout << num << endl; return 0; } C #include <stdio.h> void fun(int* num, int k) { *num &= (~(1 << k)); } int main() { int num = 7; int k = 1; fun(&num, k); printf("%d ", num); return 0; } Java public class Main { public static void fun(int[] num, int k) { num[0] &= (~(1 << k)); } public static void main(String[] args) { int[] num = {7}; int k = 1; fun(num, k); System.out.println(num[0]); } } Python def fun(num, k): num[0] &= ~(1 << k) num = [7] k = 1 fun(num, k) print(num[0]) JavaScript function fun(num, k) { num[0] &= ~(1 << k); } let num = [7]; let k = 1; fun(num, k); console.log(num[0]);

It will unset the kth bit of num

It will unset the all bits of num

It will clear all the bits of bits

What will the below code snippet do? C++ #include <iostream> using namespace std; int main() { int num = 5; cout << (~num + 1) << endl; return 0; } C #include <stdio.h> int main() { int num = 5; printf("%d ", (~num + 1)); return 0; } Java public class Main { public static void main(String[] args) { int num = 5; System.out.println(~num + 1); } } Python num = 5 print(~num + 1) JavaScript let num = 5; console.log(~num + 1);

It will print 2's complement of a number.

It will print 1.s complement of a number.

Quiz about Top MCQs on Bitwise Algorithms and Bit Manipulations with Answers

Question 1

What is the return value of following function for arr[] = {9, 12, 2, 11, 2, 2, 10, 9, 12, 10, 9, 11, 2} and n is size of this array.

C++

int fun(int arr[], int n) {
    int x = arr[0];
    for (int i = 1; i < n; i++)
        x = x ^ arr[i];
    return x;
}

C

int fun(int arr[], int n)
{
    int x = arr[0];
    for (int i = 1; i < n; i++)
        x = x ^ arr[i];
    return x;
}

Java

public int fun(int[] arr) {
    int x = arr[0];
    for (int i = 1; i < arr.length; i++)
        x = x ^ arr[i];
    return x;
}

Python

def fun(arr):
    x = arr[0]
    for i in range(1, len(arr)):
        x ^= arr[i]
    return x

JavaScript

function fun(arr) {
    let x = arr[0];
    for (let i = 1; i < arr.length; i++)
        x ^= arr[i];
    return x;
}

0
9
12
2

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Question 2

What does the following C expression do? x = (x<<1) + x + (x>>1);

Multiplies an integer with 7
Multiplies an integer with 3.5
Multiplies an integer with 3
Multiplies an integer with 8

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Question 3

What does the following expression do?

 x = x & (x-1)

Sets all bits as 1
Makes x equals to 0
Turns of the rightmost set bit
Turns of the leftmost set bit

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Question 4

Consider the following code snippet for checking whether a number is power of 2 or not.

C++

/* Incorrect function to check if x is power of 2*/
bool isPowerOfTwo (unsigned int x) 
{ 
  return (!(x&(x-1))); 
}

C

/* Incorrect function to check if x is power of 2*/
bool isPowerOfTwo (unsigned int x) 
{ 
  return (!(x&(x-1))); 
}

Java

// Incorrect function to check if x is power of 2
public static boolean isPowerOfTwo(unsigned int x) {
  return (x & (x - 1)) == 0;
}

Python

# Incorrect function to check if x is power of 2
def is_power_of_two(x):
    return (x & (x - 1)) == 0

JavaScript

// Incorrect function to check if x is power of 2
function isPowerOfTwo(x) {
  return (x & (x - 1)) === 0;
}

What is wrong with above function?

It does reverse of what is required
It works perfectly fine for all values of x.
It does not work for x = 0
It does not work for x = 1

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Question 5

What is the output of the following code snippet?

C++

#include <iostream>
using namespace std;

void fun(int& num, int k) { num &= (~(1 << k)); }
int main()
{
    int num = 7;
    int k = 1;
    fun(num, k);
    cout << num << endl;
    return 0;
}

C

#include <stdio.h>

void fun(int* num, int k) { *num &= (~(1 << k)); }
int main() {
    int num = 7;
    int k = 1;
    fun(&num, k);
    printf("%d\n", num);
    return 0;
}

Java

public class Main {
    public static void fun(int[] num, int k) { num[0] &= (~(1 << k)); }
    public static void main(String[] args) {
        int[] num = {7};
        int k = 1;
        fun(num, k);
        System.out.println(num[0]);
    }
}

Python

def fun(num, k):
    num[0] &= ~(1 << k)

num = [7]
k = 1
fun(num, k)
print(num[0])

JavaScript

function fun(num, k) {
    num[0] &= ~(1 << k);
}

let num = [7];
let k = 1;
fun(num, k);
console.log(num[0]);

It will unset the all bits of num
It will clear all the bits of bits
It will unset the kth bit of num
None

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Question 6

what will do the following code in bit manipulation?

C++

int function(int n)
{
    if (n % 4 == 0)
        return n;
    if (n % 4 == 1)
        return 1;
    if (n % 4 == 2)
        return n + 1;
    else
        return 0;
}

C

int function(int n) {
    if (n % 4 == 0)
        return n;
    if (n % 4 == 1)
        return 1;
    if (n % 4 == 2)
        return n + 1;
    else
        return 0;
}

Java

public int function(int n) {
    if (n % 4 == 0)
        return n;
    if (n % 4 == 1)
        return 1;
    if (n % 4 == 2)
        return n + 1;
    else
        return 0;
}

Python

def function(n):
    if n % 4 == 0:
        return n
    if n % 4 == 1:
        return 1
    if n % 4 == 2:
        return n + 1
    else:
        return 0

JavaScript

function function(n) {
    if (n % 4 === 0)
        return n;
    if (n % 4 === 1)
        return 1;
    if (n % 4 === 2)
        return n + 1;
    else
        return 0;
}

It will return the last set bit in a number.
It will return the first set bit in a number.
It will xor of two numbers.
It will give the xor of numbers from 1 to N.

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Question 7

Right shift(>>) and Left shift(<<) are equivalent to _____ by 2.

Multiply and divide
Divide and multiply
Addition and subtraction
Subtraction and addition

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Question 8

You are given a list of 5 integers and these integers are in the range from 1 to 6. There are no duplicates in list. One of the integers is missing in the list. Which of the following expression would give the missing number. ^ is bitwise XOR operator. ~ is bitwise NOT operator. Let elements of list can be accessed as list[0], list[1], list[2], list[3], list[4]

list[0] ^ list[1] ^ list[2] ^ list[3] ^ list[4]
|list[0] ^ list[1] ^ list[2] ^ list[3] ^ list[4] ^ 1 ^ 2 ^ 3 ^ 4 ^ 5 ^ 6
list[0] ^ list[1] ^ list[2] ^ list[3] ^ list[4] ^ 1 ^ 2 ^ 3 ^ 4 ^ 5
~(list[0] ^ list[1] ^ list[2] ^ list[3] ^ list[4])

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Question 9

If we want to invert all the bits of a number, then which bitwise operator should be used?

~
&
^
|

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Question 10

What will the below code snippet do?

C++

#include <iostream>
using namespace std;
int main()
{
    int num = 5;
    cout << (~num + 1) << endl;
    return 0;
}

C

#include <stdio.h>
int main() {
    int num = 5;
    printf("%d\n", (~num + 1));
    return 0;
}

Java

public class Main {
    public static void main(String[] args) {
        int num = 5;
        System.out.println(~num + 1);
    }
}

Python

num = 5
print(~num + 1)

JavaScript

let num = 5;
console.log(~num + 1);

It will print 2's complement of a number.
It will print 101.
It will print 1.s complement of a number.
None

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