Nsryjdtyk

I have the following code

#include <stdio.h>

#include <stdlib.h>

#include <stddef.h>

#include <string.h>



#include <json/json.h>



int main(int argc, char **argv)

{

      json_object *new_obj;

      char buf = "{ "foo": "bar", "foo2": "bar2", "foo3": "bar3" }"

      new_obj = json_tokener_parse(buf);

      printf("The value of foo is %s" /*What I have to put here?*/);

      printf("The value of foo2 is %s" /*What I have to put here?*/);

      printf("The value of foo3 is %s" /*What I have to put here?*/);

      json_object_put(new_obj);

}

I knwo that we have to use json_tokener_parse() to parse json strings but then I do not know how to extract values from the json_object new_obj as indicated in the comments in the code above

How to get json values after json_tokener_parse() ?

First you need to get the json_object to a specific node:

json_object *obj_foo = json_object_object_get(new_obj, "foo");

...then you can use the appropriate getter to obtain the value of the node in a specific type:

char *foo_val = json_object_get_string(obj_foo2);

So, in short, you could do:

printf("The value of foo is %s", 

    json_object_get_string(json_object_object_get(new_obj, "foo"))

);

Obviously, it's better to do it in multiple steps so that you can check for errors (in this case: null pointers) and prevent undefined behavior and such.

You can find the JSON C API documentation here.

Hi pls see this sample (TESTED). copy and paste into ur IDE

#include <stdio.h>

#include <json/json.h>



int main()

{

  /*Declaring the json data's in json format*/

  char buf = "{ "Name": "xxxxx", "Id": 101, "Voting_eligible": true }";



  /*Declaring the Json_object.To pass the Json string to the newly created Json_object*/

  json_object *new_obj = json_tokener_parse(buf);



  /*To get the data's then we have to get to the specific node by using the below function*/



  json_object *obj_Name;//Declaring the object to get  store the value of the Name

  obj_Name = json_object_object_get(new_obj,"Name");//This in-built func used to traverse through specific node



  json_object *obj_Id;//Declaring the object to get  store the value of the  Id

  obj_Id = json_object_object_get(new_obj,"Id");//This in-built func used to traverse through specific node



  json_object *obj_Vote;//Declaring the object to get  store the value of the  Vote

  obj_Vote = json_object_object_get(new_obj,"Voting_eligible");//This in-built func used to traverse through specific node



  /* To store the values we use temp char */

  char *Name = json_object_get_string(obj_Name);// This is in-built func to get the string(value) from "json_object_object_get()"

  char *Id = json_object_get_string(obj_Id);

  char *Vote = json_object_get_string(obj_Vote);









  /* we can also use like this statement directly to reduce the pgm size */

  //  printf("Name : %sn",json_object_get_string(json_object_object_get(new_obj, "Name")));

  //  printf("Id : %sn",json_object_get_string(json_object_object_get(new_obj, "Id")));

  //  printf("Voting_eligible : %sn",json_object_get_string(json_object_object_get(new_obj, "Voting_eligible")));



  printf("Name : %sn",Name);

  printf("Id : %sn",Id);

  printf("Voting_eligible : %sn",Vote);



  json_object_put(new_obj);// to return the pointer to its originalobjects





}

The accepted answer shows how to use json_object_object_get function which is now deprecated.

json_object_object_get_ex should be used instead.

const char *json = "{ "Name": "xxxxx", "Id": 101, "Voting_eligible": true }";

json_object *root_obj = json_tokener_parse(json);



json_object *tmp;

if (json_object_object_get_ex(root_obj, "Name", &tmp){

    // Key Name exists

    printf("Name: %sn", json_object_get_string(tmp));

    // Name: xxxxx

}