.NET Data Types Tutorial

Introduction

.NET provides a rich set of data types that help you model data efficiently, ensuring type safety and performance. This tutorial walks through the most commonly used data types, their ranges, and practical usage examples.

Primitive Types

Type	Alias	Size	Range
System.Boolean	bool	1 byte	true/false
System.Byte	byte	1 byte	0 – 255
System.SByte	sbyte	1 byte	-128 – 127
System.Char	char	2 bytes	Unicode 0 – 65535
System.Int16	short	2 bytes	-32,768 – 32,767
System.UInt16	ushort	2 bytes	0 – 65,535
System.Int32	int	4 bytes	-2,147,483,648 – 2,147,483,647
System.UInt32	uint	4 bytes	0 – 4,294,967,295
System.Int64	long	8 bytes	-9,223,372,036,854,775,808 – 9,223,372,036,854,775,807
System.UInt64	ulong	8 bytes	0 – 18,446,744,073,709,551,615
System.Single	float	4 bytes	±1.5 × 10⁻⁴⁵ to ±3.4 × 10³⁸
System.Double	double	8 bytes	±5.0 × 10⁻³²⁴ to ±1.7 × 10³⁰⁸
System.Decimal	decimal	16 bytes	±1.0 × 10⁻²⁸ to ±7.9 × 10²⁸
System.String	string	Reference	Unicode text

bool isActive = true;
int age = 30;
double balance = 1234.56;
string message = "Hello, .NET!";

Reference Types

Reference types store references to objects on the managed heap. They include class, interface, delegate, array, and string.

class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

Person p = new Person { Name = "Alice", Age = 28 };
Console.WriteLine(p.Name);

Nullable Types

Value types can be made nullable using the ? suffix, allowing them to represent an undefined state.

int? optionalNumber = null;
if (optionalNumber.HasValue)
    Console.WriteLine(optionalNumber.Value);
else
    Console.WriteLine("No value");