Explain the difference between reference and value types.

In C#, types are divided into value types and reference types.

• Value types store data directly. When assigned or passed to a method, the value is copied. Examples: int, double, struct, enum.

• Reference types store a reference to an object in memory (heap). When assigned, the reference is copied, not the object itself. Examples: class, string, array.

Main differences:

• Storage: Value types are usually stored on the stack, reference types on the heap.
• Passing: Value types are passed by value (copy), reference types by reference (reference is copied).
• Mutability: Changes in a copy of a value type do not affect the original; changes through a reference in a reference type are reflected in all references.

Example:

int a = 5;
int b = a; // copy of the value
b = 10;
// a is still 5

class Person { public string Name; }
Person p1 = new Person { Name = "Alice" };
Person p2 = p1; // copy of the reference
p2.Name = "Bob";
// p1.Name is now "Bob"

Understanding the difference is important for memory management and program behavior.