Gtkmm probe

#include "mywindow.h"
#include <iostream>
#include <sstream>

MyWindow::MyWindow()
{
    area = new MyArea();
    mybox1 = new Gtk::Box(Gtk::ORIENTATION_VERTICAL);
    mybox2 = new Gtk::Box(Gtk::ORIENTATION_HORIZONTAL);
    edita = new Gtk::Entry();
    editb = new Gtk::Entry();
    editc = new Gtk::Entry();
    editx1 = new Gtk::Entry();
    editx2 = new Gtk::Entry();
    editm = new Gtk::Entry();
    labela = new Gtk::Label("a:");
    labelb = new Gtk::Label("b:");
    labelc = new Gtk::Label("c:");
    labelx1 = new Gtk::Label("x1:");
    labelx2 = new Gtk::Label("x2:");
    labelm = new Gtk::Label("m:");
    buttonOK = new Gtk::Button("OK");
    set_title("Random");
    set_default_size(900, 400);
    mybox1->set_homogeneous(false);
    mybox2->set_homogeneous(false);
    add(*mybox1);
    mybox1->pack_start(*area);
    area->show();
    mybox2->pack_start(*labela);
    labela->show();
    mybox2->pack_start(*edita);
    edita->show();
    mybox2->pack_start(*labelb);
    labelb->show();
    mybox2->pack_start(*editb);
    editb->show();
    mybox2->pack_start(*labelc);
    labelc->show();
    mybox2->pack_start(*editc);
    editc->show();
    mybox2->pack_start(*labelx1);
    labelx1->show();
    mybox2->pack_start(*editx1);
    editx1->show();
    mybox2->pack_start(*labelx2);
    labelx2->show();
    mybox2->pack_start(*editm);
    editm->show();
    mybox2->pack_start(*labelm);
    labelm->show();
    mybox1->pack_start(*mybox2);
    mybox2->show();
    buttonOK->signal_clicked().connect(sigc::bind<-1, Glib::ustring>(
                                       sigc::mem_fun(*this, &MyWindow::on_button_clicked), "buttonOK"));
    mybox1->pack_start(*buttonOK);
    buttonOK->show();
    mybox1->show();
}

MyWindow::~MyWindow()
{
    delete buttonOK;
    delete labela;
    delete edita;
    delete labelb;
    delete editb;
    delete labelc;
    delete editc;
    delete labelx1;
    delete editx1;
    delete labelx2;
    delete editx2;
    delete labelm;
    delete editm;
    delete mybox2;
    delete mybox1;
}

void MyWindow::on_button_clicked(Glib::ustring data)
{
    Glib::ustring sa = edita->get_text();
    Glib::ustring sb = editb->get_text();
    Glib::ustring sc = editc->get_text();
    Glib::ustring sx1 = editx1->get_text();
    Glib::ustring sx2 = editx2->get_text();
    Glib::ustring sm = editm->get_text();
    if(sa!="")
    {
        std::stringstream out(sa);
        out >> a;
    }
    else a = defa;
    if(sb!="")
    {
        std::stringstream out(sb);
        out >> b;
    }
    else b = defb;
    if(sc!="")
    {
        std::stringstream out(sc);
        out >> c;
    }
    else c = defc;
    if(sx1!="")
    {
        std::stringstream out(sx1);
        out >> x1;
    }
    else x1 = defx1;
    if(sx2!="")
    {
        std::stringstream out(sx2);
        out >> x2;
    }
    else x2 = defx2;
    if(sm!="")
    {
        std::stringstream out(sm);
        out >> m;
    }
    else m = defm;
    area->seta(a);
    area->setb(b);
    area->setc(c);
    area->setx1(x1);
    area->setx2(x2);
    area->setm(m);
    area->repaint();
}