C# Language Fundamentals

This section provides a deep dive into the core language constructs of C#, enabling you to build robust and efficient .NET applications.

Variables and Data Types

Understanding data types is fundamental to programming. C# offers a rich set of built-in value types and reference types.

Value Types

Value types directly contain their data. Examples include:

• int: 32-bit signed integer.
• float: Single-precision 32-bit floating-point number.
• double: Double-precision 64-bit floating-point number.
• bool: Boolean value (true or false).
• char: 16-bit Unicode character.
• struct: User-defined composite types.

Reference Types

Reference types store a reference to the object's location in memory. Examples include:

• class: User-defined composite types.
• string: Immutable sequence of Unicode characters.
• array: A fixed-size sequence of elements of the same type.
• interface: A contract that defines a set of members.

int age = 30;
string name = "Alice";
bool isActive = true;
double price = 99.99;

Operators

Operators perform operations on operands. C# supports various categories of operators:

• Arithmetic operators: +, -, *, /, %
• Comparison operators: ==, !=, <, >, <=, >=
• Logical operators: &&, ||, !
• Assignment operators: =, +=, -=, *=, /=
• Increment/Decrement operators: ++, --

int x = 10;
int y = 5;
int sum = x + y; // sum is 15
bool isGreater = x > y; // isGreater is true

Control Flow Statements

Control flow statements dictate the order in which code is executed.

Conditional Statements

• if, else if, else: Execute blocks of code based on conditions.
• switch: Select one of many code blocks to be executed.

if (temperature > 30) {
    Console.WriteLine("It's hot!");
} else if (temperature < 10) {
    Console.WriteLine("It's cold!");
} else {
    Console.WriteLine("It's moderate.");
}

Looping Statements

• for: Repeats a statement or group of statements when a control expression evaluates to true.
• while: Executes a statement or group of statements while a Boolean expression evaluates to true.
• do-while: Executes a statement or group of statements at least once, and then repeats the execution while a Boolean expression evaluates to true.
• foreach: Iterates through a collection.

for (int i = 0; i < 5; i++) {
    Console.WriteLine($"Iteration: {i}");
}

string[] fruits = {"Apple", "Banana", "Cherry"};
foreach (string fruit in fruits) {
    Console.WriteLine(fruit);
}

Methods

Methods are blocks of code that perform a specific task. They help in modularizing code and promoting reusability.

public int Add(int a, int b) {
    return a + b;
}

int result = Add(5, 3); // result is 8