You can use a standard for iteration loon on j.as_array() in order to iterate all values in the given JSON array:

for (auto& value : json.as_array()) {
    std::cout << value.as_int64() << std::endl;
}

Full example:

#include <boost/json.hpp>
#include <iostream>

int main()
{
    const char* json_str = R"([1, 2, 3, 4, 5])";
    boost::json::value j = boost::json::parse(json_str);

    if (j.is_array()) {
        for (auto& value : j.as_array()) {
            std::cout << value.as_int64() << std::endl;
        }
    }

    return 0;
}

Compile using

g++ -o json json.cpp -lboost_json

This will print

1
2
3
4
5

You can copy a boost::urls::url by using it copy constructor:

boost::urls::url url1 = boost::urls::url::parse("https://example.com/path1");
boost::urls::url url2(url1); // Copy url1 to url2 using the copy constructor

#include <boost/json.hpp>

boost::json::value j = /* ... */;
// Access nested value with key "value"
j.at("value").as_string();

Full example:

#include <boost/json.hpp>
#include <iostream>

int main() {
    // Hardcoded JSON string
    const std::string json_str = R"(
        {
            "key": "1234",
            "value": "Hello, world!"
        }
    )";

    // Parse the JSON string
    boost::json::value j = boost::json::parse(json_str);

    // Access the "value" property and print it to stdout
    std::string value = j.at("value").as_string().c_str();
    std::cout << value << std::endl; // Prints "Hello, world!"

    return 0;
}

Compile using

g++ -o json json.cpp -lboost_json

#include <boost/json.hpp>

boost::json::value j = boost::json::parse(json_str);

Full example:

#include <boost/json.hpp>
#include <iostream>

int main() {
    // Hardcoded JSON string
    const std::string json_str = R"(
        {
            "key": "1234",
            "value": "Hello, world!"
        }
    )";

    // Parse the JSON string
    boost::json::value j = boost::json::parse(json_str);

    // Access the "value" property and print it to stdout
    std::string value = j.at("value").as_string().c_str();
    std::cout << value << std::endl; // Prints "Hello, world!"

    return 0;
}

Compile using

g++ -o json json.cpp -lboost_json

#include <iostream>
#include <boost/url.hpp>

using namespace boost::urls;

int main() {
    std::string username = "myusername";
    std::string password = "mypassword";
    url_view base_url = "https://example.com/api/login";

    url encoded_url(base_url);
    encoded_url.params().set("user name", username); // With space to test proper encoding
    encoded_url.params().set("password", password);

    // Prints "https://example.com/api/login?username=my%20user%20name&password=mypassword"
    std::cout << "Encoded URL: " << encoded_url << std::endl;

    return 0;
}

Compile using

g++ -o urlhost urlhost.cpp -lboost_url

If you have an URL such as:

std::string myURL = "https://subdomain.example.com/api/test";

you can parse the hostname from it using Boost::URL (you need at least Boost 1.81.0, previous versions of boost don’t have Boost.URL) using

boost::urls::url_view url(myURL);
std::string host = url.host();

std::cout << host << std::endl; // Prints "subdomain.example.com"

Full example:

#include <string>
#include <iostream>

#include <boost/url.hpp>

int main() {
    std::string myURL = "https://subdomain.example.com/api/test";

    boost::urls::url_view url(myURL);
    std::string host = url.host();

    std::cout << host << std::endl; // Prints "subdomain.example.com"
}

Compile using

g++ -o urlhost urlhost.cpp -lboost_url