如何为应用程序设置默认选项？

Question

这是我编写的一个小应用程序。现在我想将 /h 设置为默认选项，以便用户运行它时可以获得帮助消息。有人可以帮我解决这个问题吗？

#include "Poco/Util/Application.h"
#include "Poco/Util/Option.h"
#include "Poco/Util/OptionSet.h"
#include "Poco/Util/HelpFormatter.h"
#include "Poco/Util/AbstractConfiguration.h"
#include "Poco/AutoPtr.h"
#include "Poco/Process.h"
#include "Poco/PipeStream.h"
#include "Poco/StreamCopier.h"
#include <fstream>
#include <iostream>

using Poco::Util::Application;
using Poco::Util::Option;
using Poco::Util::OptionSet;
using Poco::Util::HelpFormatter;
using Poco::Util::AbstractConfiguration;
using Poco::Util::OptionCallback;
using Poco::AutoPtr;
using Poco::Process;
using Poco::ProcessHandle;
using namespace std;

class SampleApp: public Application
{

    protected:  
    void defineOptions(OptionSet& options)
    {
        Application::defineOptions(options);
        options.addOption(
            Option("help", "h", "Displays help details")
                .required(false)
                .repeatable(false)
                .callback(OptionCallback<SampleApp>(this, &SampleApp::handleHelp)));

        options.addOption(
            Option("Execute", "e", "Executes a c++ code and stores output in processess.txt")
                .required(false)
                .repeatable(false)
                .callback(OptionCallback<SampleApp>(this, &SampleApp::handleExecute)));
    }

    void handleHelp(const std::string& name, const std::string& value)
    {   
        Help();
    }
    void handleExecute(const std::string& name, const std::string& value)
    {   
        Execute();
    }

    void Help()
    {
        cout << "App.exe /option";

    }
    void Execute()
    {
    std::string cmd("D:\\Projects\\sample_cpp\\Debug\\sample_cpp.exe");
        std::vector<std::string> path;
        path.push_back("");
        Poco::Pipe outPipe;
        ProcessHandle ph = Process::launch(cmd, path, 0, &outPipe, 0);
        Poco::PipeInputStream istr(outPipe);
        std::ofstream ostr("processes.txt");
        Poco::StreamCopier::copyStream(istr, ostr);
        cout << "Chk for processess.txt file" << endl;
    }

    int main(const std::vector<std::string>& args)
    {

        return Application::EXIT_OK;
    }

};

POCO_APP_MAIN(SampleApp)

Answer 1

_{OT：我喜欢 PoCo，以前用过它。这些天我更倾向于 Boost，因为编译器支持变得无处不在。 这个问题是我对侵入性/限制性框架的定义：简单的事情变得很难做。有时违背了优秀程序员的价值。}

我建议保留一个标志，如下所示：（查看_noop）

#include "Poco/Util/Application.h"
#include "Poco/Util/Option.h"
#include "Poco/Util/OptionSet.h"
#include "Poco/Util/HelpFormatter.h"
#include "Poco/Util/AbstractConfiguration.h"
#include "Poco/AutoPtr.h"
#include "Poco/Process.h"
#include "Poco/PipeStream.h"
#include "Poco/StreamCopier.h"
#include <fstream>
#include <iostream>

using Poco::Util::Application;
using Poco::Util::Option;
using Poco::Util::OptionSet;
using Poco::Util::HelpFormatter;
using Poco::Util::AbstractConfiguration;
using Poco::Util::OptionCallback;
using Poco::AutoPtr;
using Poco::Process;
using Poco::ProcessHandle;
using namespace std;

class SampleApp: public Application
{

    protected:  
    void defineOptions(OptionSet& options)
    {
        Application::defineOptions(options);
        options.addOption(
            Option("help", "h", "Displays help details")
                .required(false)
                .repeatable(false)
                .callback(OptionCallback<SampleApp>(this, &SampleApp::handleHelp)));

        options.addOption(
            Option("Execute", "e", "Executes a c++ code and stores output in processess.txt")
                .required(false)
                .repeatable(false)
                .callback(OptionCallback<SampleApp>(this, &SampleApp::handleExecute)));
    }

    void handleHelp(const std::string& name, const std::string& value)
    {   
        Help();
    }
    void handleExecute(const std::string& name, const std::string& value)
    {   
        Execute();
    }

    void Help()
    {
        _noop = false;
        cout << "App.exe /option";

    }
    void Execute()
    {
        _noop = false;
        std::string cmd("D:\\Projects\\sample_cpp\\Debug\\sample_cpp.exe");
        std::vector<std::string> path;
        path.push_back("");
        Poco::Pipe outPipe;
        ProcessHandle ph = Process::launch(cmd, path, 0, &outPipe, 0);
        Poco::PipeInputStream istr(outPipe);
        std::ofstream ostr("processes.txt");
        Poco::StreamCopier::copyStream(istr, ostr);
        cout << "Chk for processess.txt file" << endl;
    }

    SampleApp() : _noop(true) { }

    int main(const std::vector<std::string>& args)
    {
        if (_noop)
            Help();

        return Application::EXIT_OK;
    }

  private:
    bool _noop;

};

POCO_APP_MAIN(SampleApp)