Home > Backend Development > C++ > body text

What do the \'colon\' and \'auto\' keywords signify in a C range-based for loop?

Patricia Arquette
Release: 2024-11-02 04:56:30
Original
385 people have browsed it

What do the 'colon' and 'auto' keywords signify in a C   range-based for loop?

Understanding 'colon' and 'auto' in C for Loops

Comprehending the syntax of C for loops can be perplexing, especially when encountering elements like 'colon' and 'auto'.

In the specific syntax provided:

<code class="cpp">for(const auto& ioDev : deviceList)</code>
Copy after login

where 'deviceList' is defined as a vector of pointers to Device objects, the 'colon' (:) marks the separation between the loop control variable and the range or collection to be iterated over.

The keyword 'auto' is used for automatic type deduction. In this context, it means that the type of the loop control variable 'ioDev' will be automatically determined from the type of the range being iterated over. In this case, since 'deviceList' is a vector of pointers to Device objects, 'ioDev' will be a reference to a Device pointer. The const specifier preceding 'auto' ensures that 'ioDev' is a constant reference, disallowing any modifications to the referenced Device objects.

Essentially, this range-based for loop iterates through each element of 'deviceList', binding the reference to the Device pointer to the loop control variable 'ioDev'. The loop body can then operate on these pointers as necessary.

The above is the detailed content of What do the \'colon\' and \'auto\' keywords signify in a C range-based for loop?. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
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
Latest Articles by Author
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!