public MainWindow(){
		super();
		
		initMenuBar();									//˵
		initTextPane(); 								//ʼ༭
		this.setTitle("SmartCalculator");
		this.setSize(this.WINDOW_WIDTH, this.WINDOW_HEIGHT);
		this.setDefaultCloseOperation(EXIT_ON_CLOSE);
		//ôĻм
		this.setLocation((Toolkit.getDefaultToolkit().getScreenSize().width-this.WINDOW_WIDTH)/2, (Toolkit.getDefaultToolkit().getScreenSize().height-this.WINDOW_HEIGHT)/2);
		//this.setResizable(false);
		//this.setUndecorated(true);
		//this.setOpacity((float) 0.8);
		this.setVisible(true);
		
	}