Common Type System. Value and reference types in C# презентация

Common Type System. Value and reference types in C#.

AGENDA Common Type System Data Type Class Hierarchy class Object Intrinsic Data Types Variable Declaration and Initialization Implicitly Typed Local Variables C# Nullable Types. ?? Operator Value and Reference Types Shallow and deep copy

Common Type System CTS – common type sestem: defines how types are declared, used, and managed in the common language runtime, is an important part of the runtime's support for cross-language integration. CTS performs the following functions: Establishes a framework that helps enable cross-language integration, type safety, and high-performance code execution. Provides an object-oriented model that supports the complete implementation of many programming languages. Defines rules that languages must follow, which helps ensure that objects written in different languages can interact with each other. Provides a library that contains the primitive data types ( Boolean, Byte, Char, Int32, and UInt64)

The Data Type Class Hierarchy

Base class Object

Intrinsic Data Types

Variable Declaration and Initialization It is a compiler error to make use of a local variable before assigning an initial value. All intrinsic data types support a default constructor. We can create a variable using the new keyword, which automatically sets the variable to its default value: • bool variables are set to false. • Numeric data is set to 0 (or 0.0 in the case of floating-point data types). • char variables are set to a single empty character. • BigInteger variables are set to 0. (from System.Numerics.dll) • DateTime variables are set to 1/1/0001 12:00:00 AM. • Object references (including strings) are set to null.

Variable Declaration and Initialization It is more cumbersome to use the new keyword when creating a basic data type variable:

Implicitly Typed Local Variables

C# Nullable Types

C# Nullable Types and operator ??

Value and Reference Types

Value and Reference Types

Value and References Types, Assignment Operator

Parameter Modifiers

Passing Reference Types by Value and by Reference

Shallow and deep copy If you have a class or structure that contains only value types, implement your Clone() method using MemberwiseClone(): If you have a custom type that maintains other reference types, you might want to create a new object that takes into account each reference type member variable, in order to get a “deep copy.”

References MSDN:Common Type System Built-in Data Types Value and Reference Types Object class

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