我正在尝试制作一个具有包含textPanel类的SimpleWindow类的图形用户界面:classtextPanel{private:std::stringtext_m;public:textPanel(std::stringstr):text_m(str){}~textPanel();};classSimpleWindow{public:SimpleWindow();~SimpleWindow();textPaneltext_panel_m;};SimpleWindow::SimpleWindow():text_panel_m(std::stringtemp("defaultval