#include <iostream>

class MainProgram {
    public:
        MainProgram(std::string sentence) :  m_sentence(sentence){ };
        void execute();
    private:
        std::string m_sentence;
};

void MainProgram::execute() {
    std::cout << this->m_sentence << std::endl;
}

int main(int argc, char** argv)
{
    auto program = new MainProgram("Hello, world!");
    program->execute();
    return 0;
}