jsoncpp 简单示例

Here is an example of JSON data:

// Configuration options

{
    // Default encoding for text

     "encoding" : "UTF-8",


  // Plug-ins loaded at start-up

  "plug-ins" : [
        "python",
        "c++",
        "ruby"
        ],


  // Tab indent size

  "indent" : { "length" : 3, "use_space": true }

}

Code example

Json::Value root; // will contains the root value after parsing.
Json::Reader reader;

bool parsingSuccessful = reader.parse( config_doc, root );


if ( !parsingSuccessful )
{

    // report to the user the failure and their locations in the document.
      std::cout  << "Failed to parse configuration\n"
               << reader.getFormattedErrorMessages();
   return;

}



// Get the value of the member of root named 'encoding', return 'UTF-8' if there is no
// such member.
  std::string encoding = root.get("encoding", "UTF-8" ).asString();
 // Get the value of the member of root named 'encoding', return a 'null' value if
// there is no such member.
  const Json::Value plugins = root["plug-ins"];


  for ( int index = 0; index < plugins.size(); ++index )  // Iterates over the sequence
   elements.
   loadPlugIn( plugins[index].asString() );

  setIndentLength( root["indent"].get("length", 3).asInt() );

  setIndentUseSpace( root["indent"].get("use_space", true).asBool() );


// ...// At application shutdown to make the new configuration document:
// Since Json::Value has implicit constructor for all value types, it is not
// necessary to explicitly construct the Json::Value object:
  root["encoding"] = getCurrentEncoding();
  root["indent"]["length"] = getCurrentIndentLength();

  root["indent"]["use_space"] = getCurrentIndentUseSpace();
  Json::StyledWriter writer;
 // Make a new JSON document for the configuration. Preserve original comments.
  std::string outputConfig = writer.write( root );
 // You can also use streams.  This will put the contents of any JSON
// stream at a particular sub-value, if you'd like.
  std::cin >> root["subtree"];


// And you can write to a stream, using the StyledWriter automatically.
  std::cout << root;


原文详见于：http://jsoncpp.sourceforge.net/

原文链接: https://www.cnblogs.com/qiuyeyaozhuai/archive/2012/10/10/2719057.html

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