Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Demonstrating value types, reference types, and nullable reference types

// --- Value types ---
int    count    = 42;
double pi       = 3.14159;
bool   isActive = true;
char   grade    = 'A';

// Struct: value-type semantics (copied on assignment)
var point1 = new System.Drawing.Point(10, 20);
var point2 = point1;   // independent copy
point2.X = 99;
Console.WriteLine($"point1.X = {point1.X}"); // still 10

// --- Reference types ---
var list1 = new List<int> { 1, 2, 3 };
var list2 = list1;     // same reference
list2.Add(4);
Console.WriteLine($"list1.Count = {list1.Count}"); // 4 (shared object)

// --- Nullable value types ---
int? maybeNull = null;
Console.WriteLine(maybeNull.HasValue);          // False
Console.WriteLine(maybeNull.GetValueOrDefault()); // 0

// --- Nullable reference types (requires <Nullable>enable</Nullable>) ---
string? nullableStr = null;
int length = nullableStr?.Length ?? 0;          // null-conditional + null-coalescing
Console.WriteLine($"Length: {length}");

// --- Type checking ---
object obj = "hello";
if (obj is string s)
    Console.WriteLine($"String of length {s.Length}");

// --- Boxing and unboxing ---
int   num    = 7;
object boxed = num;        // boxing
int   unboxed = (int)boxed; // unboxing
Console.WriteLine(unboxed);