Lesson 2 of 40 Foundations Beginner ⏱ 25 min

Variables, Types & Operators

Learn C#'s rich type system — value types, reference types, implicit and explicit casting, string interpolation, and all the operators you need.

Part 1: Built-in Value Types

Type	Size	Range / Notes
`int`	32-bit	–2,147,483,648 to 2,147,483,647
`long`	64-bit	Very large integers
`double`	64-bit float	±5.0×10⁻³²⁴ to ±1.7×10³⁰⁸
`decimal`	128-bit	Precise financial calculations
`bool`	1-bit	true / false
`char`	16-bit	Single Unicode character

Part 2: var, Implicit & Explicit Casting

var age = 30; // Compiler infers int
var price = 9.99m; // decimal literal
double d = age; // Implicit: int → double ✅
int i = (int)d; // Explicit cast — may lose precision
string s = age.ToString();// Convert int to string
int parsed = int.Parse("42");

Part 3: String Interpolation & Verbatim Strings

string name = "Alice";
int score = 98;

// Interpolated string (preferred)
string msg = $"Player {name} scored {score} points!";

// Verbatim string (no escape sequences)
string path = @"C:UsersAliceDocuments";

// Raw string literals (C# 11+)
string json = """
{ "name": "Alice", "score": 98 }
""";

Part 4: Operators Reference

Category	Operators
Arithmetic	`+ - * / % ++ --`
Comparison	`== != < > <= >=`
Logical	`&& \|\| ! & \|`
Null-handling	`?? ??= ?. ?[]`
Pattern	`is as switch`
Bitwise	`& \| ^ ~ << >>`

Variables, Types & Operators

Part 1: Built-in Value Types

Part 2: var, Implicit & Explicit Casting

Part 3: String Interpolation & Verbatim Strings

Part 4: Operators Reference

C# in Visual Studio 2026