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 ))); } What is wrong with above function?

It does reverse of what is required

It works perfectly fine for all values of x.

C Input and Output

C Operators

C++ Constructors

C Loops & Control Structure

C Structure & Union

C Macro & Preprocessor

GATE CS 2012

OS Process Management

CN Data Link Layer

Top MCQs on Linked List Data Structure with Answers

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.

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

Discuss it

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

Discuss it

Question 3

What does the following C 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

Discuss it

Question 4

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

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

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

Discuss it

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;
}

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

Discuss it

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;
}

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.

Discuss it

Question 7

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

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

Discuss it

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])

Discuss it

Question 9

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

Discuss it

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;
}

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

Discuss it

1 2 3

There are 30 questions to complete.

Last Updated :

Take a part in the ongoing discussion

Trending in News