Stack vs Heap in .NET
Stack vs Heap in .NET – What Every Developer Should Know
- When it comes to memory management in .NET, two areas matter most: Stack and Heap.
- Understanding how they work can drastically improve application efficiency and scalability.
Stack
- Stores value types (when declared locally):
- Primitives → int, float, double, decimal, bool, char, byte, short, long
- References (pointers) to Heap objects
Performance
- Allocation → O(1)
- Access → O(1)
- Deallocation → O(1) (auto, when method ends)
- Extremely fast due to LIFO (Last In, First Out)
Heap
- Stores reference types:
- class, interface, object, string, array (even arrays of value types)
- delegate, dynamic
- Also holds value types if they’re fields inside a reference type
- Managed by the Garbage Collector (GC)Managed by the Garbage Collector (GC)
Performance
- Allocation → O(1) amortized (may slow due to fragmentation or GC)
- Access → O(1)
- Deallocation → handled by GC (can be costly during collection phases)
Rule of Thumb
- Local Value Types → Stack
- Reference Types → Heap (reference lives in Stack)
- Value Types inside Reference Types → Heap
Mastering Stack vs Heap helps you:
- Write cleaner code
- Reduce unnecessary allocations
- Lower GC pressure
- Improve Performance