Explain how garbage collection works in automated memory management systems.

The Garbage Collector (GC) in automated memory management systems is responsible for automatically freeing memory that is no longer used by the program. In C#, the garbage collector operates based on object reachability tracking: if an object is not accessible from root references (such as from the stack or static variables), it is considered garbage and its memory can be released.

Main stages of the garbage collector:

1. Reachability determination — GC scans all root objects and marks all objects that can be reached.
2. Collection of unused objects — objects that are not marked as reachable are considered garbage, and their memory is freed.
3. Memory compacting — to reduce fragmentation, memory can be compressed, and references to objects are updated.

In C#, the garbage collector is implemented using generations (Generation 0, 1, 2), which increases efficiency because young objects are often quickly garbage collected, and their collection occurs more frequently than for long-lived objects.

Example:

class Program
{
    static void Main()
    {
        var obj = new object(); // object is created
        obj = null; // reference is nullified, object becomes unreachable
        GC.Collect(); // forced garbage collection (rarely used in real applications)
    }
}