Bitwise operation

Question 1

What is XOR of a number to itself

Answer 1

0

Question 2

How to use bitwise operator to check if number is even or odd?

Answer 2

If number is even, its least significant bit will be 0. For odd , its least significant bit will be 1
if ( (num & 1 )  == 1 ) 
odd number 
else 
even number

Question 3

Which bitwise operator to use to multiply number by power of 2

Answer 3

left shift operator 10«2 will give 10*4(2^2)=40 as a result

Question 4

Which bitwise operator to divide the number by power of 2?

Answer 4

right shift operator 20»2 will give 20/(2^2)=20/4=5 as a result

Question 5

How to unset the right most set bit of a number?

Answer 5

https://www.techiedelight.com/bit-hacks-part-3-playing-rightmost-set-bit-number/
n & n-1

Question 6

If number of 1-bits in 2 are 1 , how many number of bits, 4 will have ?

Answer 6

Number of bits in even number are equal to how many number of bits in its half like n/2.
In case of odd number , add 1 i.e. n/2+1

Question 7

How to know if last bit of a given number is 0 or 1

Answer 7

num & 1 =0 last bit is zero , otherwise less bit is one

Question 8

How to convert int in base 10 to base 2 string?

Answer 8

int base2=2;

Convert.ToString(123,base2); will output 1111011

Question 9

Give a string containing base 2 number(101), how can we convert it into base 10 number

Answer 9

int number=Convert.ToInt32(str,2);