Dlib库【10】——计算积分,读取xml显示

配置Dlib环境：  链接

1.计算积分

// The contents of this file are in the public domain.  See LICENSE_FOR_EXAMPLE_PROGRAMS.txt/*This example demonstrates the usage of the numerical quadrature functionintegrate_function_adapt_simp().  This function takes as input a single variablefunction, the endpoints of a domain over which the function will be integrated, and atolerance parameter.  It outputs an approximation of the integral of this function overthe specified domain.  The algorithm is based on the adaptive Simpson method outlined in:Numerical Integration method based on the adaptive Simpson method inGander, W. and W. Gautschi, "Adaptive Quadrature – Revisited,"BIT, Vol. 40, 2000, pp. 84-101*/#include <iostream>#include <dlib/matrix.h>#include <dlib/numeric_constants.h>#include <dlib/numerical_integration.h>using namespace std;using namespace dlib;// Here we the set of functions that we wish to integrate and comment in the domain of// integration.// x in [0,1]double gg1(double x){return pow(e, x);}// x in [0,1]double gg2(double x){return x*x;}// x in [0, pi]double gg3(double x){return 1 / (x*x + cos(x)*cos(x));}// x in [-pi, pi]double gg4(double x){return sin(x);}// x in [0,2]double gg5(double x){return 1 / (1 + x*x);}int main(){// We first define a tolerance parameter.  Roughly speaking, a lower tolerance will// result in a more accurate approximation of the true integral.  However, there are // instances where too small of a tolerance may yield a less accurate approximation// than a larger tolerance.  We recommend taking the tolerance to be in the// [1e-10, 1e-8] region.double tol = 1e-10;// Here we compute the integrals of the five functions defined above using the same // tolerance level for each.double m1 = integrate_function_adapt_simp(&gg1, 0.0, 1.0, tol);double m2 = integrate_function_adapt_simp(&gg2, 0.0, 1.0, tol);double m3 = integrate_function_adapt_simp(&gg3, 0.0, pi, tol);double m4 = integrate_function_adapt_simp(&gg4, -pi, pi, tol);double m5 = integrate_function_adapt_simp(&gg5, 0.0, 2.0, tol);// We finally print out the values of each of the approximated integrals to ten// significant digits.cout << "\nThe integral of exp(x) for x in [0,1] is " << std::setprecision(10) << m1 << endl;cout << "The integral of x^2 for in [0,1] is " << std::setprecision(10) << m2 << endl;cout << "The integral of 1/(x^2 + cos(x)^2) for in [0,pi] is " << std::setprecision(10) << m3 << endl;cout << "The integral of sin(x) for in [-pi,pi] is " << std::setprecision(10) << m4 << endl;cout << "The integral of 1/(1+x^2) for in [0,2] is " << std::setprecision(10) << m5 << endl;cout << endl;system("pause");return 0;}

2.读取XML并显示

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt/*读取XML显示的一个程序*/#include <dlib/xml_parser.h>#include <iostream>#include <fstream>using namespace std;using namespace dlib;// ----------------------------------------------------------------------------------------class doc_handler : public document_handler{/*As the parser runs it generates events when it encounters tags anddata in an XML file.  To be able to receive these events all you have todo is make a class that inherits from dlib::document_handler andimplements its virtual methods.   Then you simply associate aninstance of your class with the xml_parser.So this class is a simple example document handler that just printsall the events to the screen.*/public:virtual void start_document(){cout << "parsing begins" << endl;}virtual void end_document(){cout << "Parsing done" << endl;}virtual void start_element(const unsigned long line_number,const std::string& name,const dlib::attribute_list& atts){cout << "on line " << line_number << " we hit the <" << name << "> tag" << endl;// print all the tag's attributesatts.reset();while (atts.move_next()){cout << "\tattribute: " << atts.element().key() << " = " << atts.element().value() << endl;}}virtual void end_element(const unsigned long line_number,const std::string& name){cout << "on line " << line_number << " we hit the closing tag </" << name << ">" << endl;}virtual void characters(const std::string& data){cout << "Got some data between tags and it is:\n" << data << endl;}virtual void processing_instruction(const unsigned long line_number,const std::string& target,const std::string& data){cout << "on line " << line_number << " we hit a processing instruction with a target of '"<< target << "' and data '" << data << "'" << endl;}};// ----------------------------------------------------------------------------------------int main(int argc, char** argv){try{// Check if the user entered an argument to this application.  if (argc != 2){cout << "Please enter an xml file to parse on the command line" << endl;return 1;}doc_handler dh;// Now run the parser and tell it to call our doc_handler for each of the parsing// events.parse_xml(argv[1], dh);}catch (std::exception& e){cout << e.what() << endl;}}

先这样了，本来只想看看Dlib的效果追踪咋样的，结果一下子看到这么多有趣的东西……

接着去啃手势识别了…