Value Type and Reference Type in C#

What are Value Types and Reference Types?

In C#, data types are divided into two main categories: Value types and Reference types. Understanding the difference between these two is fundamental to working with variables, memory, and performance in C#.

Value Types

Value types hold the actual data in memory. When a variable of value type is assigned to another, the data is copied, meaning changes made to one variable do not affect the other. All the primitive data types in C# are value types, and they are stored in the stack memory.

Example of Value Types:

int a = 10;
int b = a;  // b gets a copy of a

a = 20;
Console.WriteLine(b);  // Output: 10
        

In this example, changing the value of a does not affect b because b holds a copy of a's original value.

Reference Types

Reference types store the reference (or address) of the data in memory, not the actual data itself. When a reference type variable is assigned to another, both variables point to the same memory location. This means that changes to one variable affect the other. Reference types are stored in the heap memory.

Example of Reference Types:

class Person
{
    public string Name;
}

Person p1 = new Person();
p1.Name = "John";

Person p2 = p1;  // p2 refers to the same object as p1
p2.Name = "Mike";

Console.WriteLine(p1.Name);  // Output: Mike
        

In this example, changing the name through p2 also changes it for p1 because both variables reference the same memory location.

Minimum and Maximum Range of Value Types

The following table lists the minimum and maximum values of common value types in C#:

Different Types of Data Types

The following table categorizes the different types of data types in C#: