Python3 Program to Rotate bits of a number

Bit Rotation: A rotation (or circular shift) is an operation similar to a shift except that the bits that fall off at one end are put back to the other end. 
In the left rotation, the bits that fall off at the left end are put back at the right end. 
In the right rotation, the bits that fall off at the right end are put back at the left end.
 

INTRODUCTION:

In this Python program, we will learn how to rotate the bits of a given number. Bit rotation, also known as bit shifting, is a technique for rotating the bits of a binary number to the left or right. This can be useful in a variety of contexts, such as in computer science and cryptography.

The program will take an integer input and a rotation distance, and will output the resulting rotated number. The program will use bit shifting and bitwise OR operations to accomplish the rotation.

We will begin by declaring the necessary variables and prompting the user for input. Next, we will use bit shifting and bitwise OR to rotate the bits of the input number according to the specified rotation distance. Finally, we will output the resulting rotated number to the console.

EXAMPLE 1: 

def rotate_bits(num, rot):
    return (num << rot) & 0xFFFFFFFF

num = int(input("Enter a number: "))
rot = int(input("Enter the number of positions to rotate: "))

result = rotate_bits(num, rot)
print("The result of the rotation is:", result)

Example: 2

Let n is stored using 8 bits. Left rotation of n = 11100101 by 3 makes n = 00101111 (Left shifted by 3 and first 3 bits are put back in last ). If n is stored using 16 bits or 32 bits then left rotation of n (000...11100101) becomes 00..0011100101000. 
Right rotation of n = 11100101 by 3 makes n = 10111100 (Right shifted by 3 and last 3 bits are put back in first ) if n is stored using 8 bits. If n is stored using 16 bits or 32 bits then right rotation of n (000...11100101) by 3 becomes 101000..0011100. 
 

# Python3 code to 
# rotate bits of number

INT_BITS = 32

# Function to left
# rotate n by d bits
def leftRotate(n, d):

    # In n<<d, last d bits are 0.
    # To put first 3 bits of n at 
    # last, do bitwise or of n<<d
    # with n >>(INT_BITS - d) 
    return (n << d)|(n >> (INT_BITS - d))

# Function to right
# rotate n by d bits
def rightRotate(n, d):

    # In n>>d, first d bits are 0.
    # To put last 3 bits of at 
    # first, do bitwise or of n>>d
    # with n <<(INT_BITS - d) 
    return (n >> d)|(n << (INT_BITS - d)) & 0xFFFFFFFF

# Driver program to
# test above functions 
n = 16
d = 2

print("Left Rotation of",n,"by"
      ,d,"is",end=" ")
print(leftRotate(n, d))

print("Right Rotation of",n,"by"
     ,d,"is",end=" ")
print(rightRotate(n, d))

# This code is contributed by
# Smitha Dinesh Semwal

Output : 

Left Rotation of 16 by 2 is 64
Right Rotation of 16 by 2 is 4

Time Complexity: O(1)

Auxiliary Space: O(1)

Please refer complete article on Rotate bits of a number for more details!

kartik

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Article Tags :

• Bit Magic
• Python
• Python Programs
• DSA
• rotation

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