C# Data Types

Introduction

Data types in C# define the kind of data that a variable can hold. C# is a statically-typed language, which means every variable must have a defined data type at compile time. Understanding data types is essential for writing efficient and error-free code.

Categories of Data Types

C# data types can be broadly categorized into two types:

1. Value Types
2. Reference Types

Value Types

Value types hold data directly. They are stored in the stack and include simple types such as integers, floating-point numbers, and structures.

Common Value Types

1. int: Represents a 32-bit signed integer.
2. double: Represents a double-precision floating-point number.
3. char: Represents a single 16-bit Unicode character.
4. bool: Represents a Boolean value (true or false).

Integer Types

byte

• Range: 0 to 255
• Size: 8 bits

byte age = 25;
Console.WriteLine("Age: " + age);

Output:

Age: 25

sbyte

• Range: -128 to 127
• Size: 8 bits

sbyte temperature = -10;
Console.WriteLine("Temperature: " + temperature);

Output:

Temperature: -10

short

• Range: -32,768 to 32,767
• Size: 16 bits

short population = 15000;
Console.WriteLine("Population: " + population);

Output:

Population: 15000

ushort

• Range: 0 to 65,535
• Size: 16 bits

ushort maxHeight = 60000;
Console.WriteLine("Max Height: " + maxHeight);

Output:

Max Height: 60000

int

• Range: -2,147,483,648 to 2,147,483,647
• Size: 32 bits

int salary = 50000;
Console.WriteLine("Salary: " + salary);

Output:

Salary: 50000

uint

• Range: 0 to 4,294,967,295
• Size: 32 bits

uint distance = 150000;
Console.WriteLine("Distance: " + distance);

Output:

Distance: 150000

long

• Range: -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
• Size: 64 bits

long worldPopulation = 7800000000L;
Console.WriteLine("World Population: " + worldPopulation);

Output:

World Population: 7800000000

ulong

• Range: 0 to 18,446,744,073,709,551,615
• Size: 64 bits

ulong galaxyStars = 250000000000UL;
Console.WriteLine("Galaxy Stars: " + galaxyStars);

Output:

Galaxy Stars: 250000000000

Floating-Point Types

float

• Range: Approximately ±1.5e−45 to ±3.4e38
• Precision: 7 digits
• Size: 32 bits

float pi = 3.14F;
Console.WriteLine("PI: " + pi);

Output:

PI: 3.14

double

• Range: Approximately ±5.0e−324 to ±1.7e308
• Precision: 15-16 digits
• Size: 64 bits

double e = 2.718281828459045;
Console.WriteLine("E: " + e);

Output:

E: 2.718281828459045

decimal

• Range: Approximately ±1.0e−28 to ±7.9e28
• Precision: 28-29 digits
• Size: 128 bits

decimal price = 199.99M;
Console.WriteLine("Price: " + price);

Output:

Price: 199.99

Character Type

char

• Range: Any valid Unicode character
• Size: 16 bits

char grade = 'A';
Console.WriteLine("Grade: " + grade);

Output:

Grade: A

Boolean Type

bool

• Values: true or false
• Size: Depends on the target platform

bool isActive = true;
Console.WriteLine("Is Active: " + isActive);

Output:

Is Active: True

Reference Types

Reference types store references to their data (objects) in memory, rather than the actual data itself. They are stored in the heap and include types such as classes, interfaces, arrays, and delegates.

Common Reference Types

1. string: Represents a sequence of characters.
2. object: The base type from which all other types derive.
3. dynamic: Represents a type that is resolved at runtime.

string

• Description: Represents a sequence of characters.

string name = "John Doe";
Console.WriteLine("Name: " + name);

Output:

Name: John Doe

object

• Description: The base type from which all other types derive.

object obj = 42;
Console.WriteLine("Object: " + obj);

Output:

Object: 42

dynamic

• Description: Represents a type that is resolved at runtime.

dynamic dynamicVar = 100;
Console.WriteLine("Dynamic Variable: " + dynamicVar);
dynamicVar = "Now I'm a string";
Console.WriteLine("Dynamic Variable: " + dynamicVar);

Output:

Dynamic Variable: 100
Dynamic Variable: Now I'm a string

Nullability

Reference types can hold a null value, indicating that the variable does not reference any object. Value types, by default, cannot be null, but you can use nullable value types to allow null values.