How does object separation occur in heaps?

In .NET, the heap is divided into two main generations: Generation 0 and Generation 1. When necessary, Generation 2 is created.

• Generation 0 (Gen 0): Newly created objects are placed here. This is the youngest and smallest heap. The garbage collector (GC) most often checks and cleans this generation. Objects that survive the collection in Gen 0 are moved to Gen 1.
• Generation 1 (Gen 1): Contains objects that have survived collection in Gen 0. GC checks this generation less frequently than Gen 0. Objects that survive collection in Gen 1 are moved to Gen 2.
• Generation 2 (Gen 2): Contains long-lived objects from Gen 1, as well as large objects. GC checks this generation the least often. Collection in Gen 2 is the most time-consuming.
• Large Object Heap (LOH): A special area of the heap for objects of size 85 KB or more. Objects in LOH are not moved by GC, as moving them is very expensive. LOH cleanup occurs along with Gen 2 collection.

The division into generations is based on the hypothesis that recently created objects are more likely to become garbage faster than long-lived objects. This approach allows GC to efficiently clean memory by focusing on the youngest generations.

// Example of creating objects in Generation 0
object obj1 = new object();
string str1 = "Hello";

// After the first Gen 0 garbage collection, if obj1 and str1 are still needed,
// they can be moved to Generation 1.

// Long-lived object
List<int> longLivedList = new List<int>();
for (int i = 0; i < 1000; i++)
{
    longLivedList.Add(i);
}
// This list may eventually move to Generation 2.

// Large object to be placed in LOH
byte[] largeArray = new byte[100 * 1024]; // Size > 85 KB