search

What is :: in c language

Apr 13, 2024 pm 06:42 PM
c languagec++

Double colon (::) in C is used for: 1. Global namespace access; 2. Namespace qualification; 3. Enum constant access; 4. Static method call; 5. Base class reference.

What is :: in c language

Double colon (::) in C

In C, double colon (::) operation The symbol has the following uses:

1. Global namespace access

  • Used when accessing global variables or functions not declared in the current namespace.
  • For example:

    ::x = 10; // 访问全局变量 x

2. Namespace qualification

  • Specify the variable or function to which Namespaces.
  • For example:

    namespace std {
    int a;
    }
    
    int main() {
    std::a = 10; // 访问 std 命名空间中的变量 a
    }

3. Enumeration constant access

  • Access in enumeration type used when using constants.
  • For example:

    enum Color {
    Red,
    Green,
    Blue
    };
    
    int main() {
    Color color = ::Color::Red; // 访问枚举常量 Red
    }

4. Static method call

  • Used when calling static class methods .
  • For example:

    class MyClass {
    public:
      static void print() {
        cout << "Hello!" << endl;
      }
    };
    
    int main() {
    MyClass::print(); // 调用静态方法 print
    }

5. Base class reference

  • Reference the base in the derived class Used when class.
  • For example:

    class Base {
    public:
      void print() {
        cout << "Base class" << endl;
      }
    };
    
    class Derived : public Base {
    public:
      void print() {
        ::Base::print(); // 引用基类方法 print
      }
    };

The above is the detailed content of What is :: in c language. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
C# .NET Development Today: Trends and Best PracticesC# .NET Development Today: Trends and Best PracticesApr 28, 2025 am 12:25 AM

The latest developments and best practices in C#.NET development include: 1. Asynchronous programming improves application responsiveness, and simplifies non-blocking code using async and await keywords; 2. LINQ provides powerful query functions, efficiently manipulating data through delayed execution and expression trees; 3. Performance optimization suggestions include using asynchronous programming, optimizing LINQ queries, rationally managing memory, improving code readability and maintenance, and writing unit tests.

C# .NET: Building Applications with the .NET EcosystemC# .NET: Building Applications with the .NET EcosystemApr 27, 2025 am 12:12 AM

How to build applications using .NET? Building applications using .NET can be achieved through the following steps: 1) Understand the basics of .NET, including C# language and cross-platform development support; 2) Learn core concepts such as components and working principles of the .NET ecosystem; 3) Master basic and advanced usage, from simple console applications to complex WebAPIs and database operations; 4) Be familiar with common errors and debugging techniques, such as configuration and database connection issues; 5) Application performance optimization and best practices, such as asynchronous programming and caching.

C# as a Versatile .NET Language: Applications and ExamplesC# as a Versatile .NET Language: Applications and ExamplesApr 26, 2025 am 12:26 AM

C# is widely used in enterprise-level applications, game development, mobile applications and web development. 1) In enterprise-level applications, C# is often used for ASP.NETCore to develop WebAPI. 2) In game development, C# is combined with the Unity engine to realize role control and other functions. 3) C# supports polymorphism and asynchronous programming to improve code flexibility and application performance.

C# .NET for Web, Desktop, and Mobile DevelopmentC# .NET for Web, Desktop, and Mobile DevelopmentApr 25, 2025 am 12:01 AM

C# and .NET are suitable for web, desktop and mobile development. 1) In web development, ASP.NETCore supports cross-platform development. 2) Desktop development uses WPF and WinForms, which are suitable for different needs. 3) Mobile development realizes cross-platform applications through Xamarin.

C# .NET Ecosystem: Frameworks, Libraries, and ToolsC# .NET Ecosystem: Frameworks, Libraries, and ToolsApr 24, 2025 am 12:02 AM

The C#.NET ecosystem provides rich frameworks and libraries to help developers build applications efficiently. 1.ASP.NETCore is used to build high-performance web applications, 2.EntityFrameworkCore is used for database operations. By understanding the use and best practices of these tools, developers can improve the quality and performance of their applications.

Deploying C# .NET Applications to Azure/AWS: A Step-by-Step GuideDeploying C# .NET Applications to Azure/AWS: A Step-by-Step GuideApr 23, 2025 am 12:06 AM

How to deploy a C# .NET app to Azure or AWS? The answer is to use AzureAppService and AWSElasticBeanstalk. 1. On Azure, automate deployment using AzureAppService and AzurePipelines. 2. On AWS, use Amazon ElasticBeanstalk and AWSLambda to implement deployment and serverless compute.

C# .NET: An Introduction to the Powerful Programming LanguageC# .NET: An Introduction to the Powerful Programming LanguageApr 22, 2025 am 12:04 AM

The combination of C# and .NET provides developers with a powerful programming environment. 1) C# supports polymorphism and asynchronous programming, 2) .NET provides cross-platform capabilities and concurrent processing mechanisms, which makes them widely used in desktop, web and mobile application development.

.NET Framework vs. C#: Decoding the Terminology.NET Framework vs. C#: Decoding the TerminologyApr 21, 2025 am 12:05 AM

.NETFramework is a software framework, and C# is a programming language. 1..NETFramework provides libraries and services, supporting desktop, web and mobile application development. 2.C# is designed for .NETFramework and supports modern programming functions. 3..NETFramework manages code execution through CLR, and the C# code is compiled into IL and runs by CLR. 4. Use .NETFramework to quickly develop applications, and C# provides advanced functions such as LINQ. 5. Common errors include type conversion and asynchronous programming deadlocks. VisualStudio tools are required for debugging.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!