C# Overview

Summary of the data types in C# with example code snippets

Value types

• bool: represents a Boolean value (true or false)

bool isCorrect = true;

• char: represents a single Unicode character

char letter = 'a';

• byte: represents an 8-bit unsigned integer

byte b = 255;

• short: represents a 16-bit signed integer

short s = -32768;

• int: represents a 32-bit signed integer

int i = 42;

• long: represents a 64-bit signed integer

long l = 1000000000L;

• float: represents a single-precision floating-point number

float f = 3.1415927f;

• double: represents a double-precision floating-point number

double d = 3.141592653589793;

• decimal: represents a decimal number with up to 28 significant digits

decimal price = 9.99M;

Reference types

• string: represents a sequence of Unicode characters

string greeting = "Hello, world!";

• object: represents an instance of any type

object obj = new object();

dynamic: represents a type that is determined at runtime

dynamic dynamicVar = "hello";
Console.WriteLine(dynamicVar.GetType()); // System.String
dynamicVar = 42;
Console.WriteLine(dynamicVar.GetType()); // System.Int32

• array: represents a collection of elements of the same type

int[] numbers = { 1, 2, 3, 4, 5 };

class: represents a blueprint for creating objects

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

Person person = new Person { Name = "Alice", Age = 30 };

• interface: represents a contract for implementing functionality

public interface IShape
{
double GetArea();
}

public class Rectangle : IShape
{
public double Width { get; set; }
public double Height { get; set; }

    public double GetArea()
    {
        return Width * Height;
    }

}

IShape shape = new Rectangle { Width = 10, Height = 20 };
double area = shape.GetArea();