Home  >  Article  >  Backend Development  >  Usage of C++ function rvalue reference parameters

Usage of C++ function rvalue reference parameters

WBOY
WBOYOriginal
2024-04-19 18:09:02904browse

In C, the rvalue reference parameter allows a function to obtain a reference to a temporary object without creating a copy. The advantages include avoiding unnecessary copies, improving performance and readability. The syntax is void func(T&& param). Note that rvalue references can only be bound to temporary objects and can only be used within functions.

C++ 函数 rvalue 引用参数的用法

Usage of C function rvalue reference parameter

In C, the rvalue reference parameter allows the function to obtain a reference to a temporary object. without creating a copy of it. This improves performance and readability.

Syntax:

void func(T&& param);

Among them:

  • && represents rvalue reference
  • param is Function parameter
  • T is of type

Advantages:

  • Avoid unnecessary copying
  • Improve performance
  • Improve code readability

Practical case:

Consider a string that converts to uppercase Function:

#include <iostream>
#include <string>

using namespace std;

void toUpperCase(string&& str) {
  for (char& c : str) {
    c = toupper(c);
  }
}

int main() {
  string input = "hello";
  toUpperCase(input);
  cout << input << endl;

  return 0;
}

In this case, when passing input to toUpperCase, there is no need to copy the string as it is a temporary object. This function will modify input directly, thus avoiding unnecessary overhead.

Output:

HELLO

Notes:

  • Only temporary objects can be bound to rvalue reference parameters.
  • rvalue references cannot be bound to existing variables.
  • rvalue references can only be used in functions, not as class members.

The above is the detailed content of Usage of C++ function rvalue reference parameters. 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