What is the difference between value types and reference types in programming?

In programming, data types are divided into value types and reference types.

• Value types store their data directly in the memory allocated for the variable. When assigned or passed to a method, the value itself is copied. In C#, primitive types (int, double, bool) and structs are considered value types.

• Reference types store a reference (pointer) to the memory location where the data is held, rather than the data itself. When assigned, only the reference is copied, not the object. Classes (class), arrays, and strings (string) are reference types.

Example:

int a = 5;
int b = a; // copies the value 5
b = 10;
// a still equals 5

class Person { public string Name; }
Person p1 = new Person { Name = "Alice" };
Person p2 = p1; // copies the reference
p2.Name = "Bob";
// p1.Name now also equals "Bob"

This distinction is important for understanding the behavior of variables when passing and modifying data.