Can you explain how Automatic Reference Counting (ARC) works in Objective-C?

ARC (Automatic Reference Counting) is a memory management mechanism in Objective-C that automatically tracks the number of references to objects and frees memory when the object is no longer used.

The principle of ARC is based on reference counting (retain count):

• When an object is created, its reference count is 1.
• When the object is assigned to a new variable, the count increases (retain).
• When a variable goes out of scope or is assigned nil, the count decreases (release).
• When the count reaches 0, the object is automatically removed from memory.

Example:

NSObject *obj = [[NSObject alloc] init]; // retain count = 1
self.property = obj; // retain count increases
obj = nil; // retain count decreases
// When all references to the object disappear, memory is freed automatically

Developers do not need to explicitly call retain/release; ARC inserts these calls at compile time, reducing the likelihood of memory management errors such as leaks or double releases.