


How to Initialize Protected Members of a Parent Class in a Child Class\'s Constructor?
Initializing Protected Members with Initialization List
In object-oriented programming, parent classes can have protected members that are accessible by child classes. When initializing child objects, it may be desirable to also initialize the protected members declared in the parent class. However, this is not as straightforward as it seems.
Consider the following example:
<code class="cpp">class Parent { protected: std::string something; }; class Child : public Parent { private: Child() : something("Hello, World!") {} };</code>
In this example, we attempt to initialize the protected member something of the parent class using the initialization list of the child class' constructor. However, the compiler will report an error: class 'Child' does not have any field named 'something'. This error occurs because the protected member something is not declared in the child class and is therefore not visible within the initialization list.
Solution
To initialize protected members of a parent class within a child class' constructor, we need to add a constructor (preferably protected) to the parent class that takes the necessary parameters to initialize these members. The child class can then use this constructor to pass the appropriate values.
Here's a revised implementation:
<code class="cpp">class Parent { protected: Parent(const std::string& something) : something(something) {} std::string something; }; class Child : public Parent { private: Child() : Parent("Hello, World!") {} };</code>
In this example, we have added a protected constructor to the Parent class that takes a string parameter and uses it to initialize the protected member something. The Child class then uses this constructor to initialize its parent's protected member during its own construction.
The above is the detailed content of How to Initialize Protected Members of a Parent Class in a Child Class\'s Constructor?. For more information, please follow other related articles on the PHP Chinese website!

C is still important in modern programming because of its efficient, flexible and powerful nature. 1)C supports object-oriented programming, suitable for system programming, game development and embedded systems. 2) Polymorphism is the highlight of C, allowing the call to derived class methods through base class pointers or references to enhance the flexibility and scalability of the code.

The performance differences between C# and C are mainly reflected in execution speed and resource management: 1) C usually performs better in numerical calculations and string operations because it is closer to hardware and has no additional overhead such as garbage collection; 2) C# is more concise in multi-threaded programming, but its performance is slightly inferior to C; 3) Which language to choose should be determined based on project requirements and team technology stack.

C isnotdying;it'sevolving.1)C remainsrelevantduetoitsversatilityandefficiencyinperformance-criticalapplications.2)Thelanguageiscontinuouslyupdated,withC 20introducingfeatureslikemodulesandcoroutinestoimproveusabilityandperformance.3)Despitechallen

C is widely used and important in the modern world. 1) In game development, C is widely used for its high performance and polymorphism, such as UnrealEngine and Unity. 2) In financial trading systems, C's low latency and high throughput make it the first choice, suitable for high-frequency trading and real-time data analysis.

There are four commonly used XML libraries in C: TinyXML-2, PugiXML, Xerces-C, and RapidXML. 1.TinyXML-2 is suitable for environments with limited resources, lightweight but limited functions. 2. PugiXML is fast and supports XPath query, suitable for complex XML structures. 3.Xerces-C is powerful, supports DOM and SAX resolution, and is suitable for complex processing. 4. RapidXML focuses on performance and parses extremely fast, but does not support XPath queries.

C interacts with XML through third-party libraries (such as TinyXML, Pugixml, Xerces-C). 1) Use the library to parse XML files and convert them into C-processable data structures. 2) When generating XML, convert the C data structure to XML format. 3) In practical applications, XML is often used for configuration files and data exchange to improve development efficiency.

The main differences between C# and C are syntax, performance and application scenarios. 1) The C# syntax is more concise, supports garbage collection, and is suitable for .NET framework development. 2) C has higher performance and requires manual memory management, which is often used in system programming and game development.

The history and evolution of C# and C are unique, and the future prospects are also different. 1.C was invented by BjarneStroustrup in 1983 to introduce object-oriented programming into the C language. Its evolution process includes multiple standardizations, such as C 11 introducing auto keywords and lambda expressions, C 20 introducing concepts and coroutines, and will focus on performance and system-level programming in the future. 2.C# was released by Microsoft in 2000. Combining the advantages of C and Java, its evolution focuses on simplicity and productivity. For example, C#2.0 introduced generics and C#5.0 introduced asynchronous programming, which will focus on developers' productivity and cloud computing in the future.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 English version
Recommended: Win version, supports code prompts!
