How can I get property name and property value from json-cpp parser?

Question

I'm using jsoncpp parser (http://jsoncpp.sourceforge.net) to parse JSON data. So, if we have the following JSON:

{ "name": "Joseph", "age": 20 }

How can I get the property name name and value Joseph, ... after age and 20? OK, we can do universally this:

string e = root.get(propertyName, defaultValue).asString();

But really what we want is something like this:

string e = root.get(name, "Mark").asString();

Now, variable e is Joseph, it works. But I have to take/write "name". I do not want to QUERY (without questioning the function I want to get "name" (name of property) and "Joseph" (value of property)).

After it would be best to store in a field (C/C++ for example):

property[name][0] = "Joseph"
property[age][0] = 20

How can I do that? Or any other ideas?

What did you learn from the documentation? What prior research did you perform before resorting to asking us? — Lightness Races in Orbit, Oct 26 '12 at 00:44
I have no idea what you're after with the last part of your question, but I've tried to fill in the property name gap in my answer below. — Platinum Azure, Oct 26 '12 at 01:24
@RePRO: Documentation lists all the available functions. Read what they do, select the ones that look useful, and put them together like lego to build a solution to your problem. — Lightness Races in Orbit, Oct 26 '12 at 09:15

Platinum Azure · Accepted Answer · 2012-10-26T01:22:36.770

6

You can get all the member names of a Json::Value object using its getMemberNames() function. That returns an object that you can iterate over using .begin() and .end(), like any other standard library container. (In fact, the return type is an alias for std::vector<std::string>.)

After you have the member names, you should be able to iterate through them and use .get(std::string &, const ValueType &) as you already are doing to get the values for each of the object's keys.

Note that JSON objects are inherently unordered, so you can't necessarily rely on that name list having any ordering whatsoever. If you want an ordered object, you should be using JSON arrays, not JSON objects.

edited Oct 26 '12 at 01:22

answered Oct 26 '12 at 00:47

Platinum Azure

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No, in C++ for future I need something like this: string age = 20; string name = "Joseph"; void fc(age, name); But we do not know about property name **name**. – RePRO Oct 26 '12 at 00:59
Edited with something you could try. – Platinum Azure Oct 26 '12 at 01:22
Better edited, thank you. What about this? `code`for each (var key in obj) { cout << "name=" << key << "value=" << obj[key]; }`code` – RePRO Oct 26 '12 at 01:30
I doubt that will work-- try it and see what it gives you. :-) – Platinum Azure Oct 26 '12 at 01:44

How can I get property name and property value from json-cpp parser?

1 Answers1