cJSON库使用：

首先从https://sourceforge.net/projects/cjson/官网下载json库，用VS创建项目，把库文件导入项目中，测试代码如下，OK!

#include"cJSON.h"
#include "stdio.h"
void main()
{
   cJSON *jsonroot;
    char *jsonchar;

    jsonroot=cJSON_CreateObject();
    cJSON_AddItemToObject(jsonroot,"token", cJSON_CreateString("701c54c5100de856915827263c92650a"));  ////mac md5
    cJSON_AddItemToObject(jsonroot,"secret", cJSON_CreateString("701c54c5100de856915827263c92650a")); //// secret mac md5

         cJSON *userInfo; 
         cJSON_AddItemToObject(jsonroot,"userInfo", userInfo=cJSON_CreateObject());    ////创建userinfo 
                 cJSON_AddItemToObject(userInfo, "userId",cJSON_CreateString(""));
                 cJSON_AddItemToObject(userInfo, "sessionId", cJSON_CreateString(""));
                 cJSON_AddItemToObject(userInfo,"location", cJSON_CreateString("zhuhai"));
         
         cJSON *voiceInfo; 
         cJSON_AddItemToObject(jsonroot,"voiceInfo", voiceInfo=cJSON_CreateObject());     
                cJSON_AddItemToObject(voiceInfo,"voiceFinished", cJSON_CreateString("flase")); //// 
                cJSON_AddItemToObject(voiceInfo,"voiceSlice", cJSON_CreateString("Yes"));
                cJSON_AddItemToObject(voiceInfo,"sliceIndex", cJSON_CreateString("0"));
                cJSON_AddItemToObject(voiceInfo,"voiceCompress", cJSON_CreateString("pcm"));  
                cJSON_AddItemToObject(voiceInfo,"voiceSampleRate", cJSON_CreateNumber(16000));
                cJSON_AddItemToObject(voiceInfo,"sessionId", cJSON_CreateString("")); 

         cJSON *driverInfo; 
         cJSON_AddItemToObject(jsonroot,"driverInfo", driverInfo=cJSON_CreateObject());     
                cJSON_AddItemToObject(driverInfo,"mac", cJSON_CreateString("3ca067585d68")); ////
                cJSON_AddItemToObject(driverInfo,"mid", cJSON_CreateString("1001"));
                cJSON_AddItemToObject(driverInfo,"exemac", cJSON_CreateString("1234567890AB"));  ////target mac

    cJSON_AddItemToObject(jsonroot,"Timestamp", cJSON_CreateString("2018-07-04 15:56:23"));
    cJSON_AddItemToObject(jsonroot,"type", cJSON_CreateString("1"));
    cJSON_AddItemToObject(jsonroot,"resultId", cJSON_CreateNumber(10));
    jsonchar=cJSON_PrintUnformatted(jsonroot);
 
    printf(jsonchar);

}