Este artículo es un comentario detallado sobre otro artículo . Por lo general, paso por allí, pero ahora, por alguna razón, me lastimé.
Ese artículo era una colección casi perfecta de conceptos erróneos en el vacío. Además, estos (conceptos erróneos) son bastante populares y se encuentran constantemente en varios blogs y colecciones de "99 preguntas de entrevista", "cómo conseguir una entrevista para un joven" o, en este caso, "hoja de trucos de C #".
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(value vs reference types)
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However, unlike classes, structs are value types and do not require heap allocation
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value reference ?
( Structs struct ):
16.4.2 Value semantics
- A variable of a struct type directly contains the data of the struct, whereas a variable of a class type contains a reference to an object that contains the data…
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struct Node
{
int data;
Node next; // error, Node directly depends on itself
}
// is an error because Node contains an instance field of its own type. Another example
struct A { B b; }
struct B { C c; }
struct C { A a; }
With classes, it is possible for two variables to reference the same object…
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stack vs heap
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EDITBIN.EXE /STACK:<stacksize> file.exe
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10.2.5 Value parameters
A parameter declared without a ref or out modifier is a value parameter.
10.2.6 Reference parameters
A parameter declared with a ref modifier is a reference parameter.
10.2.7 Output parameters
A parameter declared with an out modifier is an output parameter.
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string —
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9.2.5 The string type
The string type is a sealed class type that inherits directly from object. Instances of the string class represent Unicode character strings.
Values of the string type can be written as string literals (§7.4.5.6).
The keyword string is simply an alias for the predefined class System.String
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const vs readonly
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12.20 Constant expressions
A constant expression is an expression that shall be fully evaluated at compile-time
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15.5.3 Readonly fields
15.5.3.1 General When a field-declaration includes a readonly modifier, the fields introduced by the declaration are readonly fields. Direct assignments to readonly fields can only occur as part of that declaration or in an instance constructor or static constructor in the same class.
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15.5.3.3 Versioning of constants and static readonly fields
Constants and readonly fields have different binary versioning semantics. When an expression references a constant, the value of the constant is obtained at compile-time, but when an expression references a readonly field, the value of the field is not obtained until run-time.
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EventHandler handler = Click;
if (handler != null)
handler(this, e);
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Finalizer (destructor) ~
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15.13 Finalizers
[Note: In an earlier version of this standard, what is now referred to as a "finalizer" was called a
"destructor". Experience has shown that the term "destructor" caused confusion and often resulted to incorrect expectations, especially to programmers knowing C++. In C++, a destructor is called in a determinate manner, whereas, in C#, a finalizer is not. To get determinate behavior from C#, one should use Dispose. end note]
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An instance becomes eligible for finalization when it is no longer possible for any code to use that instance. Execution of the finalizer for the instance may occur at any time after the instance becomes eligible for finalization (§8.9).
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.Invoke(myObj, null);
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Singletone
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static Singleton singletonInstance;
static readonly Object syncRoot = new Object();
public static Singleton GetInstance()
{
if(singletonInstance == null)
lock(syncRoot)
if(singletonInstance == null)
singletonInstance = new Singleton();
return singletonInstance;
}
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public static Singleton Instance { get; } = new Singleton();
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static readonly Lazy<Singleton> lazy = new Lazy<Singleton>(() => new Singleton());
public static Singleton Instance => lazy.Value;
Y sí, esto también ya estaba en Habré , con un montón de comentarios.
PD: ¡ y dio la casualidad de que hoy se publicó un artículo tan detallado (18+) en Habré !
Parece que todo está debajo del artículo. Obviamente olvidé algo, o lo escribí mal, pero hay comentarios para esto, ¡que sea una mierda!