<div class="image-550">
<img src="https://cdn.kahimyang.com/resources-24/regex-lg2.avif" loading="lazy" alt="Java Sockets" />
</div>

<h4>
Getting Started
</h4>
<p>
To use regular expressions in C++, you need to include the &lt;regex> header:
</p>

<pre style="font-size: 90%;">
<code class="language-cpp normalize-whitespace line-numbers" >
#include &lt;iostream>
#include &lt;regex>
</code>
</pre>

<h4>
Basic Regex Operations
</h4>
<p>
The main classes you'll use are std::regex, std::smatch, std::regex_match, and std::regex_search.
</p>
<ul class="k-list">
<li>
<b>std::regex:</b> Represents a compiled regular expression.
</li>
<li>
<b>std::smatch:</b> Stores the results of a regex search.
</li>
<li>
<b>std::regex_match:</b> Checks if the entire string matches the regex.
</li>
<li>
<b>std::regex_search:</b> Searches for a match within the string.
</li>
</ul>
<h4>
Example 1: Basic Matching
</h4>
<p>
Let's start with a basic example of checking if a string matches a simple pattern.
</p>
<pre style="font-size: 90%;">
<code class="language-cpp normalize-whitespace line-numbers" >
#include &lt;iostream>
#include &lt;regex>

int main() {
    std::string text = "Hello, World!";
    std::regex pattern("Hello, World!");

    // Check if the entire string matches the pattern
    if (std::regex_match(text, pattern)) {
        std::cout &lt;&lt; "Text matches the pattern!" &lt;&lt; std::endl;
    } else {
        std::cout &lt;&lt; "Text does not match the pattern." &lt;&lt; std::endl;
    }

    return 0;
}
</code>
</pre>
<h4>
Example 2: Searching for a Pattern
</h4>
<p>
Next, let's search for a pattern within a string.
</p>
<pre style="font-size: 90%;">
<code class="language-cpp normalize-whitespace line-numbers" >
#include &lt;iostream>
#include &lt;regex>

int main() {
    std::string text = "I love C++ and Java!";
    std::regex pattern("C\\+\\+");

    // Search for the pattern in the text
    std::smatch matches;
    if (std::regex_search(text, matches, pattern)) {
        std::cout &lt;&lt; "Found a match: " &lt;&lt; matches[0] &lt;&lt; std::endl;
    } else {
        std::cout &lt;&lt; "No match found." &lt;&lt; std::endl;
    }

    return 0;
}
</code>
</pre>



How to Use Regular Expressions in C++