Type ~ storage ~ variable in C ＃

Welcome to be my reader , I hope this article can give you some help .

Preface

Today, I saw friends in the group talking about calling fans readers , This makes me very excited .

I used to pay more attention to the amount of articles I read , Has anyone forwarded , How many new concerns are added today . And now , My focus has changed , No longer care about these external things , Think about what you can write to your readers , Does what you write help you .

by the way , In the future, I will push two articles about qiafan over the weekend , I hope all readers have the honor to read , You can click it a little , Just exit again , Thank you for your support .

Review with you today C# The most basic knowledge in .

General situation ,C A program is a set of functions and data types ,C++ Is a set of functions and classes , and C# A program is a set of type declarations (JAVA equally ).

So what kind of writing counts as C# The procedure .

• C# Procedure or DLL The source code for is a set of type declarations

• For executable programs , A type declaration must contain Main Class of method

• A namespace is a way to group and name related type declarations .

// Namespace 
namespace WindowsApplication2
{
    /// <summary>
    ///  Representative class 
    /// </summary>
    class Test
    {
        // Declare and define variables or attributes 
        private int Name { get; set; }
        private string Age { get; set; }

    }
}

type

So what is the type ？

Think of a type as a template for creating data structures . The template itself is not a data structure , But it specifies the characteristics of the objects constructed by the template .

Type by name 、 The data structure used to store data members and some behaviors and constraints constitute .

So how to use types ？

This requires instantiation of the type , That is, to create an actual object from a type template . stay C# In the program , Each data item is an instance of some kind , Some of these types come with the language itself , There are plenty of them BCL Or other libraries , It can also be customized by programmers .

Storage

stay C# The data in is stored with various types of variables .

short、int and long Etc. is a simple type , This type of storage can only store one data item at a time . Array (array) Type can store multiple data items , Reference these elements by index .

However, there are other types that can contain many different types of data items , The data item individuals in these types are called members , It has a unique name . Including data members and function members .

class Test
    {
        // Data member 
        private string Name { get; set; }
        private int Age { get; set; }

        // Members of the function 
        private string GetName()
        {            
            return this.Name;
        }
    }

stay C# Provided in the 15 There are two predefined types , These include 13 Two simple types and 2 A non simple type .

Simple type

11 Number types , Various integer types , Floating point type float and double, One is called decimal High precision decimal type of . A kind of Unicode Character type char, A boolean type bool.

stay C# The numeric type in does not have a Boolean meaning .

Two non simple types

string, It's a kind of Unicode A character array .object, Is the base class for all other types .

You can also user-defined types , There is a total of 6 The type in can be created by the user .

• Class structure (class)

• Structure type (struct)

• data type (array)

• Enumeration type (enum)

• Delegate type (delegate)

• Interface type (interface)

Once the type is declared , You can create and use this type of object , Just as they are predefined types .

For any object of reference type , All its data members are stored in the heap , Whether they are value types or reference types .

remarks

Life is short , I don't want to pursue what I can't see , I just want to catch what I can see .

Originality is not easy. , Pay attention .

I am a A Hui , Thank you for reading , If it helps you , Please like it 、 forward   thank you .

I'm glad to be friends with you .

Previous recommendation

C# Class in

C# Data dictionary in Dictionary

C# The statement in

C# Namespace and assembly in