C# Syntax Fundamentals

C# Syntax

• Variables and Data Types: declared using the let keyword, e.g., int x = 5;
• Operators: arithmetic, comparison, logical, assignment, and bitwise operators
• Control Flow: if-else statements, switch statements, loops (for, while, do-while), and jump statements (break, continue, return)
• Methods: functions that can take arguments and return values, e.g., void PrintMessage(string message) { Console.WriteLine(message); }
• Classes and Objects: define classes using the class keyword, e.g., public class Person { }

Object-oriented Programming (OOP) in C#

• Encapsulation: hiding internal implementation details using access modifiers (public, private, protected)
• Inheritance: creating a new class based on an existing class using the : keyword, e.g., public class Employee : Person { }
• Polymorphism: using methods with the same name but different parameters or return types
• Abstraction: using abstract classes and interfaces to define contracts

Data Types in C#

• Value Types:
  • Integral: sbyte, byte, short, ushort, int, uint, long, ulong
  • Floating-point: float, double, decimal
  • Boolean: bool
  • Char: char
• Reference Types:
  • Classes: class
  • Interfaces: interface
  • Delegates: delegate
  • Arrays: int[], string[], etc.
• Nullable Types: using ? to indicate a type can be null, e.g., int? x = null;
• Dynamic Types: using the dynamic keyword to bypass compile-time type checking

C# Syntax

• Variables and data types are declared using the let keyword.
• Variables can be assigned a value using the assignment operator (=).
• C# supports various operators, including:
  • Arithmetic operators (e.g., +, -, *, /)
  • Comparison operators (e.g., ==, !=, <, >)
  • Logical operators (e.g., &&, ||, !)
  • Assignment operators (e.g., +=, -=, *=)
  • Bitwise operators (e.g., &, |, ^)

Control Flow

• If-else statements are used for conditional execution of code.
• Switch statements are used for executing different blocks of code based on the value of a variable.
• Loops (for, while, do-while) are used for repetitive execution of code.
• Jump statements (break, continue, return) are used to control the flow of code within loops and methods.

Methods

• Methods are functions that can take arguments and return values.
• Methods can be declared using the void keyword for no return value.
• Methods can be overloaded with different parameters.

Classes and Objects

• Classes define blueprints for objects.
• Classes are declared using the class keyword.
• Objects are instances of classes.

Object-oriented Programming (OOP) in C#

Encapsulation

• Access modifiers (public, private, protected) are used to control access to class members.
• Encapsulation hides internal implementation details of a class.

Inheritance

• Inheritance allows a new class to inherit properties and behavior from an existing class.
• The : keyword is used to specify the base class.

Polymorphism

• Polymorphism allows methods with the same name to have different parameters or return types.
• Method overriding and method overloading are examples of polymorphism.

Abstraction

• Abstraction defines contracts using abstract classes and interfaces.
• Abstract classes and interfaces define a blueprint for other classes to follow.

Data Types in C#

Value Types

• Integral data types: sbyte, byte, short, ushort, int, uint, long, ulong
• Floating-point data types: float, double, decimal
• Boolean data type: bool
• Char data type: char

Reference Types

• Classes: class
• Interfaces: interface
• Delegates: delegate
• Arrays: int[], string[], etc.

Nullable Types

• Nullable types can be assigned a null value using the ? keyword.
• Nullable types are used to indicate that a value can be null.

Dynamic Types

• The dynamic keyword bypasses compile-time type checking.
• Dynamic types are used for dynamic binding and late binding.

C# Basics

• Variables and data types are declared using the type variable_name syntax, e.g., int x;
• C# supports various operators, including arithmetic, comparison, logical, assignment, and bitwise operators, e.g., a + b, a == b, a && b
• Control flow statements include if-else statements, switch statements, while loops, for loops, and do-while loops, e.g., if (condition) { code }, while (condition) { code }
• Methods are declared using the return_type method_name syntax, e.g., int Add(int a, int b) { return a + b; }
• Classes are declared using the class keyword, e.g., public class MyClass { }

Object-oriented Programming (OOP) in C#

Classes and Objects

• Classes define the blueprint for objects, which represent real-world entities or concepts
• Objects are instances of classes, with their own set of attributes (data) and methods (functions)

Inheritance

• A child class can inherit properties and behavior from a parent class using the : keyword, e.g., public class ChildClass : ParentClass { }
• Inheritance enables code reuse and facilitates a hierarchical organization of classes

Polymorphism

• Methods can be overridden or overloaded to provide different implementations, e.g., public class Animal { public virtual void Sound() { } }
• Polymorphism allows for more flexibility and generic code

Abstraction

• Abstract classes and interfaces define abstract methods and properties, e.g., public abstract class Animal { public abstract void Sound(); }
• Abstraction helps to focus on essential features and hide implementation details

Encapsulation

• Classes can hide internal implementation details using access modifiers (public, private, protected), e.g., public class MyClass { private int myField; }
• Encapsulation promotes data hiding and reduces coupling between classes

Data Types in C#

Value Types

• Stored in memory, e.g., int, bool, float, char, enum
• Value types are copied when passed to methods, and changes do not affect the original value

Reference Types

• Stored as references to memory, e.g., class, interface, delegate, string
• Reference types are passed by reference to methods, and changes affect the original value

Nullable Types

• Allow value types to be null, e.g., int?, bool?
• Nullable types are useful for handling uncertain or missing data

Primitive Types

• Basic types, e.g., int, bool, float, char
• Primitive types are built-in and cannot be broken down further

Complex Types

• Composite types, e.g., class, struct, enum
• Complex types are composed of multiple values or objects

Type Conversion

• Implicit and explicit conversions between types, e.g., int to float, string to int
• Type conversions are necessary for assigning values of one type to variables of another type