How do I adopt features from C++17?

 
// Example of using std::optional in C++17
#include <iostream>
#include <optional>

std::optional findValue(bool found) {
    if (found) {
        return 42; // Return a value
    } else {
        return std::nullopt; // Return "nothing"
    }
}

int main() {
    auto result = findValue(true);
    if (result) {
        std::cout << "Value found: " << *result << std::endl;
    } else {
        std::cout << "No value found." << std::endl;
    }
}