c++ raw string

### C++ Raw String Usage

In C++, raw strings provide a convenient way to handle string literals containing backslashes (`\`), quotes (`"`), or other special characters without needing escape sequences. A raw string is prefixed with `R"delimiter(`)`, where `delimiter` can be any sequence of characters used to mark the end of the string.

#### Basic Syntax Example
A simple example demonstrates how raw strings work:

#include <iostream>
using namespace std;

int main() {
    cout << R"(This is a "raw" string\nIt spans multiple lines)" << endl;
}

The output will preserve both double quotes and newline characters as literal text rather than interpreting them specially[^1].

#### Using Delimiters
When dealing with complex cases involving parentheses within the string content, delimiters help avoid conflicts by adding custom markers around the string definition:

string sqlQuery = R"DELIM(SELECT * FROM users WHERE name LIKE 'O'Connor')DELIM";
cout << sqlQuery << endl;

Here, `DELIM` serves as an arbitrary delimiter chosen not present inside the actual SQL query itself[^2].

#### Practical Application Scenario
Raw strings prove particularly useful when working with regular expressions which often contain numerous backslashes requiring escaping under normal circumstances:

regex pattern(R"(\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z]{2,}\b)");
// This regex matches email addresses.

Using raw strings simplifies such patterns significantly compared to traditional methods relying heavily on manual escapes[^3].