title: Create empty json array with jsoncpp
body: <p>I have the following code:</p>
  <pre class="lang-cpp prettyprint-override"><code>void MyClass::myMethod(Json::Value&amp; jsonValue_ref)
  {
      for (int i = 0; i &lt;= m_stringList.size(); i++)
      {
          if (m_boolMarkerList[i])
          {
              jsonValue_ref.append(stringList[i]);
          }
      }
  }
  
  void MyClass::myOuterMethod()
  {
      Json::Value jsonRoot;
      Json::Value jsonValue;
      
      myMethod(jsonValue);
  
      jsonRoot[&quot;somevalue&quot;] = jsonValue;
      Json::StyledWriter writer;
      std::string out_string = writer.write(jsonRoot);
  }
      
  </code></pre>
  <p>If all markers in <code>m_boolMarkerList</code> are false, the <code>out_string</code> is <code>{ &quot;somevalue&quot; : null }</code>, but I want it to be an empty array: <code>{ &quot;somevalue&quot; : [ ] }</code></p>
  <p>Does anybody know how to achieve this?</p>
  <p>Thank you very much!</p>