nlohmann json：通过[ ]运算符读取设置object/array

除了可以通过at，还可以通过[ ]运算符来读取和设置object/array

#include <iostream>
#include <nlohmann/json.hpp>
using namespace std;
using json = nlohmann::json;int main()
{json data = R"({"name": "xiaoming","age": 10, "parent":   [{"father" : "zhang","age" : 40},{"mother" : "wang","age" : 36}]})"_json;cout<<data["name"]<<endl;cout<<data["parent"][0]["age"]<<endl;data["parent"][0]["age"] = 42;cout<<data<<endl;return 0;
}

运行程序输出：

"xiaoming"
40
{"age":10,"name":"xiaoming","parent":