how to parse vector<struct> format

[FantasyJXF]

I'd like to parse the json fromat like this

#include "json.hpp"

using json = nlohmann::json;
struct Image
{
    std::string url;
    int width;
    int height;
    Image(){
        url = "";
        width = -1;
        height = -1;
    };
    Image(std::string url,int width, int height):
        url(url),width(width),height(height){}
};

namespace ns {
    // a simple struct to model a person
    struct session {
        std::vector<Image> ImageUrls;
        std::string msg;
        int code;
        struct returnBody {
            int ComicId;
        }body;
        struct bboxes
        {
            std::string cords;
        }box;
    };
    void to_json(json& j, const session& s);
    void from_json(const json& j, session& s);
}

void ns::to_json(json& j, const ns::session& s) {
    j = json{
        {"ImageUrls", {json::parse(s.ImageUrls)}},
        {"msg", s.msg},
        {"code", s.code},
        {"returnBody", {
            {"ComicId", s.body.ComicId}}
        },
        {"result", {
            {"boxes", s.box.cords}}
        }
    };

}

void ns::from_json(const json& j, ns::session& s) {
    j.at("ImageUrls").get_to(s.ImageUrls);
    j.at("msg").get_to(s.msg);
    j.at("code").get_to(s.code);
    j.at("returnBody").at("ComicId").get_to(s.body.ComicId);
    j.at("result").at("boxes").get_to(s.box.cords);
}

But my to_json and from_json part runs into error. Would U please tell me how to realize this part?
Mostly vector<struct> part.
Thanks

• Compiler: /c++/4.2.1
• Operating system: MAC OS

Which version of the library did you use?

• latest release version 3.7.3
• other release - please state the version: ___
• the develop branch

[FantasyJXF]

Sorry to bother, I checked many issues, and worked it out.

The compelete source code main.cpp is as follows:

#include <iostream>
#include <vector>
#include <string>
#include <iomanip>
#include "json.hpp"

using namespace std;
using json = nlohmann::json;

namespace ns {
    struct Image
    {
        std::string url;
        int width;
        int height;
        Image(){
            url = "";
            width = -1;
            height = -1;
        };
        Image(std::string url,int width, int height):
                url(url),width(width),height(height){}
    };
    void to_json(json& j, const Image& s);
    void from_json(const json& j, Image& s);

    // a simple struct to model a person
    struct session {
        std::vector<Image> ImageUrls;
        std::string msg;
        int code;
        struct returnBody {
            int ComicId;
        }body;
        struct bboxes
        {
            std::string cords;
        }box;
    };
    void to_json(json& j, const session& s);
    void from_json(const json& j, session& s);
} // ns

void ns::to_json(json& j, const ns::Image& s) {
    j = json{
            {"url", s.url},
            {"width", s.width},
            {"height", s.height}
        };
}

void ns::from_json(const json& j, ns::Image& s) {
    j.at("url").get_to(s.url);
    j.at("width").get_to(s.width);
    j.at("height").get_to(s.height);
}

void ns::to_json(json& j, const ns::session& s) {
    j = json{
        {"ImageUrls", {s.ImageUrls}},
        {"msg", s.msg},
        {"code", s.code},
        {"returnBody", {
            {"ComicId", s.body.ComicId}}
        },
        {"result", {
            {"boxes", s.box.cords}}
        }
    };
}

void ns::from_json(const json& j, ns::session& s) {
    j.at("ImageUrls").get_to(s.ImageUrls);
    j.at("msg").get_to(s.msg);
    j.at("code").get_to(s.code);
    j.at("returnBody").at("ComicId").get_to(s.body.ComicId);
    j.at("result").at("boxes").get_to(s.box.cords);
}

int main()
{
    ns::session Sess;
    Sess = ns::session({{{"https",0,1}, {"htpp",0,1}}, "Successful", 200, 0, "1234,2345"});
    json j = Sess;
    std::cout << std::setw(4) << j << "\n\n";

    return 0;
}

The CMakeLists.txt is as follows:

cmake_minimum_required(VERSION 3.14)
project(json_parse)

set(CMAKE_BUILD_TYPE "debug")
add_executable(json_parse main.cpp)
set_property(TARGET json_parse PROPERTY CXX_STANDARD 11)