Add the Qt windows

mainwindow.cpp

@@ -0,0 +1,19 @@
+#include "mainwindow.hpp"
+#include "./ui_mainwindow.h"
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+    , ui(new Ui::MainWindow)
+    , playwindow(new playWindow)
+{
+    ui->setupUi(this);
+    connect(ui->playButton, &QPushButton::clicked, this, [=]{
+    playwindow->show();
+    this->hide();});
+}
+
+MainWindow::~MainWindow()
+{
+    delete ui;
+}
+