CODEWITHSUNDEEP
c++jsonelementadditionrapidjson
AlexC_JEng
AlexC_JEng

Reputation: 113

rapidjson - change object - add element/item

how do I add a member to a rapidjson object and then print it?

for example add 

 itemtwo => "world" ;

to this object:

{"itemone":"hello"}

I tried

 char buff[] = "{\"itemone\":\"hello\"}";
 rapidjson::Document json_obj;
 if(json_obj.Parse<0>(buff.c_str()).HasParseError() == false){        
    json_obj["itemtwo"].SetString("world");
    rapidjson::StringBuffer strbuf;
    rapidjson::Writer<rapidjson::StringBuffer> writer(strbuf);
    json_obj.Accept(writer);
    cout<<strbuf.GetString()<<endl;
 }

I get the following output:

{"itemone":"hello"}

meaning no change. What am I doing wrong?

Upvotes: 1

Views: 6849

Answers (1)

Milo Yip
Milo Yip

Reputation: 5072

json_obj["itemtwo"] can only find member with that name, which is not exist. It does not create a new entry (as in std::map).

To manipulate objects, use AddMember() and other related member functions, e.g.

json_obj.AddMember("itemone", "hello", json_obj.GetAllocator());

You may refer to rapidjson user guide and/or the tutorial.cpp in the package.

Upvotes: 4

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