Question

The code below shows a sample that I’ve used recently to explain the different behaviour of structs and classes to someone brand new to development. Is there a better way of doing so? (Yes – the code uses public fields – that’s purely for brevity)

namespace StructsVsClasses {     class Program     {         static void Main(string[] args)         {             sampleStruct struct1 = new sampleStruct();             struct1.IntegerValue = 3;             Console.WriteLine('struct1.IntegerValue: {0}', struct1.IntegerValue);              sampleStruct struct2 = struct1;             Console.WriteLine();             Console.WriteLine('struct1.IntegerValue: {0}', struct1.IntegerValue);             Console.WriteLine('struct2.IntegerValue: {0}', struct2.IntegerValue);             struct1.IntegerValue = 5;             Console.WriteLine();             Console.WriteLine('struct1.IntegerValue: {0}', struct1.IntegerValue);             Console.WriteLine('struct2.IntegerValue: {0}', struct2.IntegerValue);              sampleClass class1 = new sampleClass();             class1.IntegerValue = 3;             Console.WriteLine();             Console.WriteLine('class1.IntegerValue: {0}', class1.IntegerValue);              sampleClass class2 = class1;             Console.WriteLine();             Console.WriteLine('class1.IntegerValue: {0}', class1.IntegerValue);             Console.WriteLine('class2.IntegerValue: {0}', class2.IntegerValue);             class1.IntegerValue = 5;             Console.WriteLine();             Console.WriteLine('class1.IntegerValue: {0}', class1.IntegerValue);             Console.WriteLine('class2.IntegerValue: {0}', class2.IntegerValue);              Console.ReadKey();         }     }      struct sampleStruct     {         public int IntegerValue;     }      class sampleClass     {         public int IntegerValue;     } } 

Answer 1

The difference might be easier to understand when the struct/class is a member of another class.

Example with class:

class PointClass {   int double X;   int double Y; }  class Circle {   PointClass Center = new PointClass() { X = 0, Y = 0; } }  static void Main() {   Circle c = new Circle();   Console.WriteLine(c.Center.X);   c.Center.X = 42;   Console.WriteLine(c.Center.X); } 

Output:

0 42 

Example with struct:

struct Point {   int double X;   int double Y; }  class Circle {   PointStruct Center = new PointStruct() { X = 0, Y = 0; } }  static void Main() {   Circle c = new Circle();   Console.WriteLine(c.Center.X);   c.Center.X = 42;   Console.WriteLine(c.Center.X); } 

Output:

0 0