What is a Race Condition in simple terms?

Race Condition is a situation where the outcome of a program depends on the order of execution of multiple parallel operations, and this order is unpredictable.

A simple example: two threads try to increment a counter simultaneously. If both read the old value, increment it, and write it back, the final value will only increase by 1 instead of 2.

As a result, due to concurrent access to a shared resource without synchronization, data can become incorrect.

To avoid race conditions, synchronization mechanisms are used: mutexes, locks, atomic operations.

Example in Python using a mutex:

import threading

counter = 0
lock = threading.Lock()

def increment():
    global counter
    with lock:
        temp = counter
        temp += 1
        counter = temp

threads = [threading.Thread(target=increment) for _ in range(1000)]
for t in threads:
    t.start()
for t in threads:
    t.join()

print(counter)  # Expected 1000