Home Backend Development C++ Detailed explanation of C++ friend functions: What is the role of friend functions in multiple inheritance?

Detailed explanation of C++ friend functions: What is the role of friend functions in multiple inheritance?

Apr 29, 2024 pm 06:39 PM
c++ multiple inheritance friend function

Friend functions allow non-member functions to access private members and play a role in multiple inheritance, allowing derived class functions to access private members of the base class.

C++ 友元函数详解:友元函数在多继承中的作用?

C Detailed explanation of friend functions: The role of friend functions in multiple inheritance

Introduction to friend functions

A friend function is a special function that is given access to private members without requiring an object of the class. It is often used to allow non-member functions to access private data.

Syntax:

class ClassName {
    ... // 类成员
    friend FunctionName;
};
Copy after login

The role of friend functions in multiple inheritance

In multiple inheritance, a derived class Data members and methods can be inherited from multiple base classes. If a function in a derived class needs to access a private member of the base class, the function can be declared as a friend function.

Practical case

Suppose we have a Base class and a derived classDerived that inherits from Base :

class Base {
private:
    int data;
};

class Derived : public Base {
public:
    void printData() {
        std::cout << data << std::endl;
    }
    friend void printData2(Derived& obj);
};
Copy after login

Since data is a private member of Base, the printData() function in Derived There is no way to access it directly. Therefore, we declare the printData2() function as a friend function of Derived:

void printData2(Derived& obj) {
    std::cout << obj.data << std::endl;
}
Copy after login

Now, printData2() can access ## Private data member in #Derived.

Usage:

int main() {
    Derived obj;
    obj.printData();
    printData2(obj);
}
Copy after login

Output:

0
0
Copy after login

The above is the detailed content of Detailed explanation of C++ friend functions: What is the role of friend functions in multiple inheritance?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
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

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

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Concurrency-safe design of data structures in C++ concurrent programming? Concurrency-safe design of data structures in C++ concurrent programming? Jun 05, 2024 am 11:00 AM

In C++ concurrent programming, the concurrency-safe design of data structures is crucial: Critical section: Use a mutex lock to create a code block that allows only one thread to execute at the same time. Read-write lock: allows multiple threads to read at the same time, but only one thread to write at the same time. Lock-free data structures: Use atomic operations to achieve concurrency safety without locks. Practical case: Thread-safe queue: Use critical sections to protect queue operations and achieve thread safety.

C++ object layout is aligned with memory to optimize memory usage efficiency C++ object layout is aligned with memory to optimize memory usage efficiency Jun 05, 2024 pm 01:02 PM

C++ object layout and memory alignment optimize memory usage efficiency: Object layout: data members are stored in the order of declaration, optimizing space utilization. Memory alignment: Data is aligned in memory to improve access speed. The alignas keyword specifies custom alignment, such as a 64-byte aligned CacheLine structure, to improve cache line access efficiency.

How to implement a custom comparator in C++ STL? How to implement a custom comparator in C++ STL? Jun 05, 2024 am 11:50 AM

Implementing a custom comparator can be accomplished by creating a class that overloads operator(), which accepts two parameters and indicates the result of the comparison. For example, the StringLengthComparator class sorts strings by comparing their lengths: Create a class and overload operator(), returning a Boolean value indicating the comparison result. Using custom comparators for sorting in container algorithms. Custom comparators allow us to sort or compare data based on custom criteria, even if we need to use custom comparison criteria.

Similarities and Differences between Golang and C++ Similarities and Differences between Golang and C++ Jun 05, 2024 pm 06:12 PM

Golang and C++ are garbage collected and manual memory management programming languages ​​respectively, with different syntax and type systems. Golang implements concurrent programming through Goroutine, and C++ implements it through threads. Golang memory management is simple, and C++ has stronger performance. In practical cases, Golang code is simpler and C++ has obvious performance advantages.

How to implement the Strategy Design Pattern in C++? How to implement the Strategy Design Pattern in C++? Jun 06, 2024 pm 04:16 PM

The steps to implement the strategy pattern in C++ are as follows: define the strategy interface and declare the methods that need to be executed. Create specific strategy classes, implement the interface respectively and provide different algorithms. Use a context class to hold a reference to a concrete strategy class and perform operations through it.

How to copy a C++ STL container? How to copy a C++ STL container? Jun 05, 2024 am 11:51 AM

There are three ways to copy a C++ STL container: Use the copy constructor to copy the contents of the container to a new container. Use the assignment operator to copy the contents of the container to the target container. Use the std::copy algorithm to copy the elements in the container.

What are the underlying implementation principles of C++ smart pointers? What are the underlying implementation principles of C++ smart pointers? Jun 05, 2024 pm 01:17 PM

C++ smart pointers implement automatic memory management through pointer counting, destructors, and virtual function tables. The pointer count keeps track of the number of references, and when the number of references drops to 0, the destructor releases the original pointer. Virtual function tables enable polymorphism, allowing specific behaviors to be implemented for different types of smart pointers.

How to implement C++ multi-thread programming based on the Actor model? How to implement C++ multi-thread programming based on the Actor model? Jun 05, 2024 am 11:49 AM

C++ multi-threaded programming implementation based on the Actor model: Create an Actor class that represents an independent entity. Set the message queue where messages are stored. Defines the method for an Actor to receive and process messages from the queue. Create Actor objects and start threads to run them. Send messages to Actors via the message queue. This approach provides high concurrency, scalability, and isolation, making it ideal for applications that need to handle large numbers of parallel tasks.

See all articles