OpenCV 输入输出XML和YAML文件

 #include <opencv2/core/core.hpp>
 #include <iostream>
 #include <string>

 using namespace cv;
 using namespace std;

 class MyData
 {
 public:
     MyData() : A(), X(), id()
     {}
     explicit MyData(int) : A(), X(CV_PI), id("mydata1234") // explicit to avoid implicit conversion
     {}
     void write(FileStorage& fs) const                        //Write serialization for this class
     {
         fs << "{" << "A" << A << "X" << X << "id" << id << "}";
     }
     void read(const FileNode& node)                          //Read serialization for this class
     {
         A = (int)node["A"];
         X = (double)node["X"];
         id = (string)node["id"];
     }
 public:   // Data Members
     int A;
     double X;
     string id;
 };

 //These write and read functions must be defined for the serialization in FileStorage to work
 void write(FileStorage& fs, const std::string&, const MyData& x)
 {
     x.write(fs);
 }
 void read(const FileNode& node, MyData& x, const MyData& default_value = MyData()){
     if(node.empty())
         x = default_value;
     else
         x.read(node);
 }

 // This function will print our custom class to the console
 ostream& operator<<(ostream& out, const MyData& m)
 {
     out << "{ id = " << m.id << ", ";
     out << "X = " << m.X << ", ";
     out << "A = " << m.A << "}";
     return out;
 }

 int main(int ac, char** av)
 {
     if (ac != )
     {
         help(av);
         return ;
     }

     string filename = av[];
     { //write
         Mat R = Mat_<uchar>::eye(, ),
             T = Mat_<double>::zeros(, );
         MyData m();

         FileStorage fs(filename, FileStorage::WRITE);

         fs << "iterationNr" << ;
         fs << "strings" << "[";                              // text - string sequence
         fs << "image1.jpg" << "Awesomeness" << "baboon.jpg";
         fs << "]";                                           // close sequence

         fs << "Mapping";                              // text - mapping
         fs << "{" << "One" << ;
         fs <<        "Two" <<  << "}";               

         fs << "R" << R;                                      // cv::Mat
         fs << "T" << T;

         fs << "MyData" << m;                                // your own data structures

         fs.release();                                       // explicit close
         cout << "Write Done." << endl;
     }

     {//read
         cout << endl << "Reading: " << endl;
         FileStorage fs;
         fs.open(filename, FileStorage::READ);

         int itNr;
         //fs["iterationNr"] >> itNr;
         itNr = (int) fs["iterationNr"];
         cout << itNr;
         if (!fs.isOpened())
         {
             cerr << "Failed to open " << filename << endl;
             help(av);
             return ;
         }

         FileNode n = fs["strings"];                         // Read string sequence - Get node
         if (n.type() != FileNode::SEQ)
         {
             cerr << "strings is not a sequence! FAIL" << endl;
             return ;
         }

         FileNodeIterator it = n.begin(), it_end = n.end(); // Go through the node
         for (; it != it_end; ++it)
             cout << (string)*it << endl;

         n = fs["Mapping"];                                // Read mappings from a sequence
         cout << "Two  " << (int)(n["Two"]) << "; ";
         cout << "One  " << (int)(n["One"]) << endl << endl; 

         MyData m;
         Mat R, T;

         fs["R"] >> R;                                      // Read cv::Mat
         fs["T"] >> T;
         fs["MyData"] >> m;                                 // Read your own structure_

         cout << endl
             << "R = " << R << endl;
         cout << "T = " << T << endl << endl;
         cout << "MyData = " << endl << m << endl << endl;

         //Show default behavior for non existing nodes
         cout << "Attempt to read NonExisting (should initialize the data structure with its default).";
         fs["NonExisting"] >> m;
         cout << endl << "NonExisting = " << endl << m << endl;
     }

     cout << endl
         << "Tip: Open up " << filename << " with a text editor to see the serialized data." << endl;

     return ;
 }