Bitwise XOR related programming problems

Certainly! Here are a few programming problems involving bitwise XOR operators:

Problem 1: Counting Bits

Write a function that takes an integer as input and returns the number of bits set to 1 in its binary representation. Use the bitwise XOR operator to solve this problem.

Example:
Input: 9
Binary representation: 1001
Output: 2

Problem 2: Single Number

Given an array of integers, where every element appears twice except for one, find that single number. Solve this problem using the bitwise XOR operator.

Example:
Input: [2, 4, 5, 4, 2]
Output: 5

Problem 3: XOR Linked List

Implement a doubly linked list where each node has a reference to both the previous and next nodes, and an additional field xor, which is the bitwise XOR of the addresses of the previous and next nodes. Implement the following operations:

Insertion of a new node at the beginning of the list
Traversal of the list in both forward and backward directions
Use the bitwise XOR operator to perform the XOR operations.

Problem 4: Flipping Bits

Given a positive integer, flip its binary representation (0s become 1s and 1s become 0s) using the bitwise XOR operator.

Example:
Input: 14 (binary: 1110)
Output: 1 (binary: 0001)

Problem 5: Swap variables

Example:
Input: a = 3, b = 9
Output: a = 9, b = 3

These problems should help you practice and understand the usage of bitwise XOR operators in programming.