How does the automatic memory management mechanism detect objects that are no longer accessible in the program?

In C#, the automatic memory management mechanism is the garbage collector (GC). It identifies objects that are no longer accessible by traversing the object graph starting from root references such as static variables, local variables on the stack, etc.

If an object is not reachable from the root references, it means there are no references to it, and it is considered inaccessible (garbage). Such an object is subject to removal by the garbage collector.

The process roughly looks like this:

1. The GC starts from the root references and marks all reachable objects.
2. All objects that were not marked are considered inaccessible.
3. The memory occupied by inaccessible objects is freed.

Thus, the garbage collector automatically cleans up memory from objects that the program no longer uses.