How to output boost property tree as JSON encoded string?

Question

Sometimes it is very useful to create JSON encoded strings for representing and exchanging data. What is be best way of encoding a Boost property tree into a JSON string?

Answer 1

Here is a sample code for doing that task:

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
#include <boost/optional.hpp>
#include <iostream>
#include <sstream>
#include <cstdlib>

int main()
{
    boost::property_tree::ptree pt;
    pt.put("Test", "string");
    pt.put("Test2.inner0", "string2");
    pt.put("Test2.inner1", "string3");
    pt.put("Test2.inner2", 1234);

    std::stringstream ss;
    boost::property_tree::json_parser::write_json(ss, pt);

    std::cout << ss.str() << std::endl;

    return 0;
}

To compile this code with GCC:

g++ main.cpp -lboost_system -o SamplePT_JSON

And here is the expected output:

{
    "Test": "string",
    "Test2":
    {
        "inner0": "string2",
        "inner1": "string3",
        "inner2": "1234"
    }
}