Day 48: Python Program To Clear Rightmost Set Bit of a Number

 

def clear_rightmost_set_bit(n):

    """

    Clears the rightmost set bit of the given number.

    :param n: The input number

    :return: The number with the rightmost set bit cleared

    """

    return n & (n - 1)

num = int(input("Enter a non-negative integer: "))  

result = clear_rightmost_set_bit(num)

print(f"Original number: {num} (Binary: {bin(num)})")

print(f"Number after clearing rightmost set bit: {result} (Binary: {bin(result)})")

#source code --> clcoding.com 

Code Explanation:

1. Function Definition

def clear_rightmost_set_bit(n):

    """

    Clears the rightmost set bit of the given number.

    :param n: The input number

    :return: The number with the rightmost set bit cleared

    """

    return n & (n - 1)

Key Points:

Rightmost Set Bit:

The rightmost set bit is the first 1 from the right in the binary representation of the number.

For example:

10 (binary: 1010) → The rightmost set bit is the second position from the right (2^1).

18 (binary: 10010) → The rightmost set bit is the fifth position from the right (2^4).

Clearing the Rightmost Set Bit:

The operation n & (n - 1) clears the rightmost set bit. Here's how:

Subtracting 1 from n flips all bits to the right of the rightmost set bit and flips the rightmost set bit to 0.

The & operation (bitwise AND) keeps all other bits unchanged but ensures the rightmost set bit is cleared.

Example:

For n = 10 (binary: 1010):

n - 1 = 9 (binary: 1001)

n & (n - 1) = 1010 & 1001 = 1000 (decimal: 8)

2. Input Handling

num = int(input("Enter a non-negative integer: "))  

Prompts the user to input a non-negative integer and stores it in num.

3. Call the Function

result = clear_rightmost_set_bit(num)

Calls the function clear_rightmost_set_bit with the input number num.

Stores the result (the number after clearing the rightmost set bit) in result.

4. Display the Results

print(f"Original number: {num} (Binary: {bin(num)})")

print(f"Number after clearing rightmost set bit: {result} (Binary: {bin(result)})")

bin():

Converts the integer into its binary representation (as a string prefixed with 0b).

For example:

bin(10) → '0b1010'

bin(8) → '0b1000'

Displays:

The original number and its binary representation.

The result after clearing the rightmost set bit and its binary representation.

Output:

Original number: 18 (Binary: 0b10010)

Number after clearing rightmost set bit: 16 (Binary: 0b10000)

Source