Cannot read some data in json file

[zj1838277795]

I am a newbie. I am doing an Android web application, the code for parsing the json file is as follows
{
"name":"HelloWorld",
"description":"Simple web example application to demonstrate",
"package":"com.example.helloworld",
"version":"0.1.0",
"start_url":"index.html",
"icons":[
{
"src":"res/img/appicon.png"
}
],
"developer":{
"name":"Example Developer",
"url":"http://www.example.com/",
"email":"[email protected]"
}
}
and my cpp code is as follows

std::string showJson(std::string cni, std::string cnj){
using json = nlohmann::json;
std::ifstream fin("/data/data/iecas.jsonshow.commanager/lib/manifest.json");
if(!fin) return "fin==null";
json j;
fin >> j;
fin.close();
if(cni == "name"&&cnj==" ") return j["name"];
if(cni == "description"&&cnj==" ") return j["description"];
if(cni == "package"&&cnj==" ") return j["package"];
if(cni == "version"&&cnj==" ") return j["version"];
if(cni == "start_url"&&cnj==" ") return j["start_url"];
if(cni == "developer"&&cnj=="name") return j["developer"]["name"];
if(cni == "developer"&&cnj=="url") return j["developer"]["url"];
if(cni == "developer"&&cnj=="email") return j["developer"]["email"];
if(cni == "developer"&&cnj==" ") return j["developer"];
if(cni == "icons"&&cnj==" ") return j["icons"];
}

I want to know how to read the string of "icons". When i use j["icons"] or j["developer"], my web app has crashed. j["developer"]["name"] and j["name"] are no problem.

[gregmarr]

The icons and developer entries aren't strings. The first is an array, and the second is an object. You can't convert them to a string like that. If you really do want the full JSON content of that entry as a string, you can use j["icons"].dump(), which will give you a string like this:

[{ "src": "res/img/appicon.png" }]

[zj1838277795]

在icons和developer项不是字符串。第一个是数组，第二个是对象。您不能将它们转换为这样的字符串。如果您确实希望该条目的完整JSON内容作为字符串，则可以使用j["icons"].dump()，它将为您提供如下字符串：

[{ "src": "res/img/appicon.png" }]

Thanks