Bit_Masking

What does the following 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

Suppose we have a set {1,  2, 3}. Find the XOR of all the subsets of the set.

• 1

• 2

• 3

• 0

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

• multiply and divide

• divide and multiply

• addition and subtraction

• subtraction and addition

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

• ~

• &

• |

• ^

What is the result of the following expression? (num ^ 0)

• it will print 0

• it will print num

• it will print 1

• none

Which of these is not a bitwise operator?

• &

• &=

• |=

• <=

public static void main(String[] args) {

byte z = 16;

int x;

x = z << 3;

System.out.println("Value of z= " + z);

System.out.println("Value of x= " + x);

}

• Value of z= 16

  Value of x= 128

• Value of z= 16

  Value of x= 2

• Value of z= 1

  Value of x= 128

• Value of z= 1

  Value of x= 2

public static void main(String[] args) {

int x;

x = 10;

x = x >> 1;

System.out.println(x);

}

• 10

• 5

• 20

• error

public static void main(String[] args) {

int a = 3;

int b = 6;

int c = a | b;

int d = a & b;

System.out.println(c + " " + d);

}

• 2 7

• 7 2

• 3 6

• 6 3

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;

}

• 0

• 9

• 12

• 2