C programming :Handy Bitwise Expressions

Index	Expression	Purpose	Remarks
1	X & 1	Check whether number is odd or even	All numbers are interms of 0’s and 1’s and hence it is sufficient check the last bit
2	X << 1	Multiply by 2
3	X >> 1	Divide by 2( Integer Division
4	~X+1	Negative the number	Negative numbers are represented by two complement. (one’s complement +1)
5	X ^ all’ones	Bit toggling (equivalent to ~)
6	X >> 31	To find out the sign of number X.	Result is 0 or 1 based on the sign.
7	Mask = (X-Y) >> 31 Result = (Mask & X) | (~Mask & Y)	Min(X, Y) without using comparisons	Mask contains all zeros if Y is less than or equal to X and all ones if X is less than Y.
8	Mask = (X-Y) >> 31 Result = (Mask & Y) | (~Mask & X)	Max(X, Y) without using comparisons	Mask contains all zeros if X is greater than or equal to Y and all ones if Y is greater than X.