The goal of this homework is to practice the GUI development using QT and the observer pattern. The main window of your program should be designed as follows with two buttons and a slider bar whose value is between 0 and 100. For your convenience an executable is also provided. You can download and run the executable to see how the program works. Below is a brief description of the GUI. Each time the user clicks the Create New Window button, a new window with the following design pops up. This new dialog window has two labels: one with a fixed value Value and another with a dynamic value whose initial value is 0. When the user slides the slider bar, for each popup window, this label displays the value of the slider bar. On any popup window, if the user clicks the reset button, the slider of the main window will be reset to 0. On the main window, if the user clicks the Delete Last Window button, the dialog window that popped up the last is closed.