Bit operation highlights

In this article, 2 'K represents the k power of 2

The k power of 1 divided by 2 can be computed using bits:

N/2 'K = n> K

The bitwise operation can be used to obtain the remainder of the K-power pair of 2:

N % 2 'K = N & (1 <k)-1)

For example, 100% 32

The binary value of 100 is 1100100.

(1 <5)-1) equal to 31 is 0011111

The two data phases get 100, so

100% 32 = 4

3 For integer N, from the low position, set its K-bit (0 <= k <= 31) to 1:

N = n | (1 <K)

4 For integer N, from the low position, set its K-bit (0 <= k <= 31) to 0:

N = N &~ (1 <K)

5 For integer N, from the low position, test whether its K-bit (0 <= k <= 31) is 1. If it is 1, return a number greater than 0, otherwise, 0 is returned.

Return N & (1 <K)

　　

6. For integer N, determine whether it is an odd or even number.

If N & 1 is greater than 0, n is an odd number; otherwise, n is an even number.

　　

7 For integer N, if n is an odd number, the N minus 1 is converted into an even number. If n is an even number, the N plus 1 is converted into an odd number.

N = n ^ 1

　　

8 For an odd number of N, the following properties are available:

(N-1) ^ n = 1

　　

9 maximum int

01 1111111111 1111111111 1111111111

Max_int = ~ (1 <31)

　　

10 smallest int

10 0000000000 0000000000 0000000000

Min_int = (1 <31)

　　

11. Change the value of 1 to 0.

For example: 111000 ---> 110000

N = N-(N &-N)

　　

12. Determine whether two integers are of the same number.

# Define mask 0x80000000

Flag = (X & Mask) ^ (Y & Mask)

If the flag is 0, it indicates different numbers. Otherwise, the same number is used.

　　

13. Exchange two values without temporary variables

 

To swap values of A and B, use the following value assignment statement:
A = A then B;
B = B then;
A = A then B;

14 bitset C language implementation

 

 

[Transfer] http://kenby.iteye.com/blog/1011480