Python Program to Swap Two Numbers Using Bitwise XOR (With Explanation & Example)

 

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If you are learning Python or preparing for coding interviews, you might have come across the swapping problem. But sometimes interviewers ask a slightly different variation—swap two numbers using the bitwise XOR operator.

At first this looks confusing especially if you are not familiar with bitwise operations. however once you understand the logic behind XOR the concept becomes simple and interesting.

This type of question is commonly asked in interviews to test your understanding of low-level operations and how values are handled internally in programming.

I personally recommend trying this method step by step. when you execute the code yourself, you will clearly see how the values change without using any extra variable.

In this article we will learn how to swap two numbers in Python using the bitwise XOR operator without using a temporary variable.

Before we start - basics :

Swapping means exchanging the values of two variables.

For example :

a = 5 and b = 10

After swapping :

a = 10 and b = 5

In this method we use the XOR (^) operator instead of arithmetic or tuple methods.

Question :

Write a Python program to swap two integers using bitwise XOR.

Method: Using XOR operator

Code:

# Author: P.Prabhas

# Function to swap numbers using XOR
def swap_xor(a, b):
    # Swap using XOR
    a = a ^ b
    b = a ^ b
    a = a ^ b
    return a, b

# Take input from user
a = int(input("Enter first number: "))
b = int(input("Enter second number: "))

# Print before swapping
print("Before swapping:", a, b)

# Call function
a, b = swap_xor(a, b)

# Print after swapping
print("After swapping:", a, b)

Output:

Enter first number: 5
Enter second number: 10
Before swapping: 5 10
After swapping: 10 5

How it works :

Let's take an example: a = 5 and b = 10

Let us see how values change step by step :

step 1:
a = a ^ b

step 2:
b = a ^ b

step 3:
a = a ^ b

Final result : a = 10, b = 5 (values swapped)

Example with actual values :

a = 5, b = 10

a = a ^ b → 5 ^ 10 = 15
b = a ^ b → 15 ^ 10 = 5 
a = a ^ b → 15 ^ 5 = 10

Final result : a = 10, b = 5

In this method XOR combines and restores values. when we apply XOR multiple times it helps us retrieve the original values without using any extra variable.

Simple idea : XOR mixes the values and then brings them back step by step.

Important concept behind XOR :

The XOR operator follows a simple rule:

X ^ Y ^ Y = X

This means if we apply XOR twice with the same value, we get the original number back.

That is why this method works without needing a temporary variable.

Key points :

• NO extra variable is used
• Works using bitwise operations
• Useful for understanding low-level logic
• Common interview question
• Helps improve problem-solving skills

You can also read this:

• Python Program to Swap Two Numbers Without using Temporary Variable
•  Python Program to Reverse an Integer Number

Interview tip :

When asked this question first explain the normal swapping method, then explain the XOR approach. this shows both your basic and advanced understanding.

Frequently asked questions (FAQ's) :

1. What is XOR in Python?

XOR is a bitwise operator that returns 1 when two bits are different and 0 when they are the same.

2. Why does XOR help in swapping?

Because applying XOR twice with the same values gives the original value back.

3. Is XOR method better than tuple method?

No, tuple method is simpler, XOR is mainly used for learning and interviews.

4. Does XOR method use extra memory?

No, it swaps values without using extra variable.

5. Is XOR method used in real projects?

Not commonly, but it is useful for understanding bitwise operations.

Conclusion:

Swapping two integers using bitwise XOR looks a little bit tricky at first, but once you understand the logic it becomes simple and interesting.

This method helps you understand how bitwise operations work internally and improves your logical thinking.

Practice this method along with other swapping techniques to strengthen your programming skills.

That's all for today friends.

Keep coding, keep learning

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