解析JSON文件（C ++ Boost）

Question

我想使用Boost（属性树）库来解析以下有效的JSON文件：

{
    "user": {
        "userID": "5C118C8D-AA65-49C0-B907-348DE87D6665",
        "dateProperty": "05-06-2015"
    },
    "challenges": [
        {
            "question#1": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        },
        {
            "question": "answer",
            "value": 5
        }
    ] }

我确实验证了JSON格式是否正确。

我还咨询了几个网站，如：

• Boost 1.46.1，属性树：如何迭代ptree接收子ptree？
• http://www.technical-recipes.com/2014/using-boostproperty_tree/

但我仍然没有得到正确的结果。 我想收集“用户”和“挑战”作为键/值对。 最好的结果是将“挑战”（问题/答案）和用户信息（userID，dateProperty）写入可以写入std：map的std ::对。

任何建议，将不胜感激？

Answer 1

我想像往常一样，你对ptree如何存储JSON数组感到困惑？

这是一个快速演示：

住在Coliru

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
#include <iostream>
#include <fstream>

int main()
{
    using namespace boost::property_tree;

    ptree pt;
    read_json(std::cin, pt);

    for (auto& challenge : pt.get_child("challenges"))
        for (auto& prop : challenge.second)
            std::cout << prop.first << ": " << prop.second.get_value<std::string>() << "\n";
}

打印：

question#1: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5
question: answer
value: 5