Simple example of parsing and consuming JSON array with boost::property_tree

boost_property_tree_json_array.cpp

#ifdef _MSC_VER
#include <boost/config/compiler/visualc.hpp>
#endif
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
#include <boost/foreach.hpp>
#include <cassert>
#include <exception>
#include <iostream>
#include <sstream>
#include <string>

int main()
{
    try
    {
        std::stringstream ss;
        ss << "{ \"root\": { \"values\": [1, 2, 3, 4, 5 ] } }";

        boost::property_tree::ptree pt;
        boost::property_tree::read_json(ss, pt);

        BOOST_FOREACH(boost::property_tree::ptree::value_type &v, pt.get_child("root.values"))
        {
            assert(v.first.empty()); // array elements have no names
            std::cout << v.second.data() << std::endl;
        }
        return EXIT_SUCCESS;
    }
    catch (std::exception const& e)
    {
        std::cerr << e.what() << std::endl;
    }
    return EXIT_FAILURE;
}

Can you show the way to generate this format { "root": { "values": [1, 2, 3, 4, 5 ] } }
using same boost tree json library. ?

Because boost tree json , converts number/values to string forms. So I wanted to know how we can generate above json.

@santoshkamblecpp The https://www.boost.org/doc/libs/1_74_0/doc/html/property_tree/parsers.html says

JSON values are mapped to nodes containing the value. However, all type information is lost; numbers, as well as the literals "null", "true" and "false" are simply mapped to their string form.

Thus, write your own serialising function (or search the StackOverflow) or use different library (e.g. https://github.com/boostorg/json)

@santoshkamblecpp The https://www.boost.org/doc/libs/1_74_0/doc/html/property_tree/parsers.html says

JSON values are mapped to nodes containing the value. However, all type information is lost; numbers, as well as the literals "null", "true" and "false" are simply mapped to their string form.

Thus, write your own serialising function (or search the StackOverflow) or use different library (e.g. https://github.com/boostorg/json)

Thank you!

Hi there,
I am searching 1.instrument_name, 2.bids, 3.asks from json below:

{"jsonrpc":"2.0","method":"subscription","params":{"channel":"book.BTC-PERPETUAL.raw","data":{"type":"change","timestamp":1635513739435,"prev_change_id":6807100702,"instrument_name":"BTC-PERPETUAL","change_id":6807100703,"bids":[["new",60772.0,50.0]],"asks":[]}}}

have there any iteration for these three fields?
like I am still confusing because I use your example code.

Thanks in advance.