Find the Only Non Repeating Element Using XOR in DSA C - Build from Scratch

Find the Only Non Repeating Element Using XOR

📖 Scenario: Imagine you have a list of numbers where every number appears twice except for one number that appears only once. You want to find that unique number quickly.

🎯 Goal: Build a C program that finds the only number in an array that does not repeat, using the XOR operation.

📋 What You'll Learn

Create an integer array called numbers with the exact values: 4, 1, 2, 1, 2

Create an integer variable called result and initialize it to 0

Use a for loop with variable i to iterate over the array numbers

Inside the loop, update result by XORing it with numbers[i]

Print the value of result which is the only non-repeating element

💡 Why This Matters

🌍 Real World

Finding unique elements quickly is useful in error detection, data cleaning, and network packet analysis.

💼 Career

Understanding bitwise operations like XOR is important for roles in embedded systems, security, and performance-critical software.

1

Create the array of numbers

Create an integer array called numbers with the exact values 4, 1, 2, 1, 2.

DSA C

# Your code here

Hint

Use curly braces to list the numbers inside the array.

2

Initialize the result variable

Create an integer variable called result and set it to 0.

DSA C

int numbers[] = {4, 1, 2, 1, 2};
# Your code here

Hint

Set result to zero before starting the XOR operations.

3

Use a for loop to XOR all elements

Use a for loop with variable i to iterate over the array numbers. Inside the loop, update result by XORing it with numbers[i].

DSA C

int numbers[] = {4, 1, 2, 1, 2};
int result = 0;
# Your code here

Hint

Use result ^= numbers[i]; inside the loop to XOR each element.

4

Print the only non-repeating element

Write a printf statement to print the value of result.

DSA C

int numbers[] = {4, 1, 2, 1, 2};
int result = 0;
for (int i = 0; i < 5; i++) {
    result ^= numbers[i];
}
# Your code here

Hint

Use printf("%d\n", result); to print the unique number.