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jsoncons::encode_json

Encode a C++ data structure to a JSON formatted string or stream. encode_json will work for all types that have json_type_traits defined.

#include <jsoncons/encode_json.hpp>

template <class T, class Container>
void encode_json(const T& val,
                 Container& s, 
                 const basic_json_encode_options<Container::value_type>& options = 
                     basic_json_encode_options<Container::value_type>()); (1)

template <class T, class CharT>
void encode_json(const T& val,
                 std::basic_ostream<CharT>& os, 
                 const basic_json_encode_options<CharT>& options = 
                     basic_json_encode_options<CharT>()); (2)

template <class T, class Container>
void encode_json_pretty(const T& val,
                        Container& s, 
                        const basic_json_encode_options<Container::value_type>& options = 
                            basic_json_encode_options<Container::value_type>()); (3) (since 0.155.0)

template <class T, class CharT>
void encode_json_pretty(const T& val,
                        std::basic_ostream<CharT>& os, 
                        const basic_json_encode_options<CharT>& options = 
                            basic_json_encode_options<CharT>()); (4) (since 0.155.0)

template <class T, class CharT>
void encode_json(const T& val, 
                 basic_json_visitor<CharT>& encoder); (5)

template <class T, class Container>
void encode_json(const T& val, 
                 Container& s, 
                 indenting line_indent); (6)

template <class T, class Container>
void encode_json(const T& val,
                 Container& s, 
                 const basic_json_encode_options<Container::value_type>& options, 
                 indenting line_indent); (7)

template <class T, class CharT>
void encode_json(const T& val, 
                 std::basic_ostream<CharT>& os, 
                 indenting line_indent); (8)

template <class T, class CharT>
void encode_json(const T& val,
                 std::basic_ostream<CharT>& os, 
                 const basic_json_encode_options<CharT>& options, 
                 indenting line_indent); (9)

(1) Encode val into a character container using the specified (or defaulted) options.

(2) Encode val to an output stream using the specified (or defaulted) options.

(3) Encode val into a character container using the specified (or defaulted) options and prettified with spaces and line breaks.

(4) Encode val to an output stream using the specified (or defaulted) options and prettified with spaces and line breaks.

(5) Convert val to json events and stream through encoder.

(6-9) Legacy overloads that indicate prettified output with line_indent parameter.

Parameters

val C++ data structure
visitor JSON output visitor
options Serialization options
os Output stream
indenting indenting::indent to pretty print, indenting::no_indent for compact output

Return value

None

Examples

Map with string-tuple pairs

#include <iostream>
#include <map>
#include <tuple>
#include <jsoncons/json.hpp>

using namespace jsoncons;

int main()
{
    using employee_collection = std::map<std::string,std::tuple<std::string,std::string,double>>;

    employee_collection employees = 
    { 
        {"John Smith",{"Hourly","Software Engineer",10000}},
        {"Jane Doe",{"Commission","Sales",20000}}
    };

    std::cout << "(1)\n" << std::endl; 
    encode_json(employees,std::cout);
    std::cout << "\n\n";

    std::cout << "(2) Again, with pretty print\n" << std::endl; 
    encode_json_pretty(employees, std::cout);
}

Output:

(1)

{"Jane Doe":["Commission","Sales",20000.0],"John Smith":["Hourly","Software Engineer",10000.0]}

(2) Again, with pretty print

{
    "Jane Doe": ["Commission","Sales",20000.0],
    "John Smith": ["Hourly","Software Engineer",10000.0]
}

Contain JSON output in an object (prettified output)

#include <iostream>
#include <map>
#include <tuple>
#include <jsoncons/json.hpp>

using namespace jsoncons;

int main()
{
    std::map<std::string, std::tuple<std::string, std::string, double>> employees =
    {
        {"John Smith",{"Hourly","Software Engineer",10000}},
        {"Jane Doe",{"Commission","Sales",20000}}
    };

    json_stream_encoder encoder(std::cout);

    encoder.begin_object();
    encoder.key("Employees");
    encode_json(employees, encoder);
    encoder.end_object();
    encoder.flush();
}

Output:

{
    "Employees": {
        "Jane Doe": ["Commission","Sales",20000.0],
        "John Smith": ["Hourly","Software Engineer",10000.0]
    }
}

Contain JSON output in an object (compressed output)

#include <iostream>
#include <map>
#include <tuple>
#include <jsoncons/json.hpp>

using namespace jsoncons;

int main()
{
    std::map<std::string, std::tuple<std::string, std::string, double>> employees =
    {
        {"John Smith",{"Hourly","Software Engineer",10000}},
        {"Jane Doe",{"Commission","Sales",20000}}
    };

    compact_json_stream_encoder encoder(std::cout);

    encoder.begin_object();
    encoder.key("Employees");
    encode_json(employees, encoder);
    encoder.end_object();
    encoder.flush();
}

Output:

{"Employees":{"Jane Doe":["Commission","Sales",20000.0],"John Smith":["Hourly","Software Engineer",10000.0]}}

See also

basic_json_visitor

basic_json_options

basic_json_encoder

decode_json