C#: What is the difference between value types and reference types in C#?

Value types — stored on stack, contain data directly. Reference types — stored on heap, contain reference.

Value types:

• Stored on stack.
• Direct data storage.
• Deallocated when out of scope.
• Examples: int, float, bool, struct, enum.

1int x = 10;  // Value type
2int y = x;   // Copy value
3y = 20;      // x still 10

Reference types:

• Stored on heap.
• Store reference (pointer).
• Garbage collected.
• Examples: class, interface, delegate, string, array.

1var arr1 = new int[] {1, 2, 3};  // Reference type
2var arr2 = arr1;                 // Copy reference
3arr2[0] = 10;                    // arr1 also changed!

Key difference:

• Value type — copies data.
• Reference type — copies reference.