Up until now, the sample programs you've created have simply printed data to the Log window using the
NSLog command. Although this can be fine for testing your program, it's definitely not how you want users to interact with your program.
If you're creating a Mac program, users expect your program to behave just like a regular Mac program by displaying pull-down menus at the top of the screen with familiar menu titles such as File, Edit, View, and Help. Users also expect to interact with your program through windows and dialog boxes that you can move, resize, and shrink from the middle of the screen.
Within each window and dialog box, users expect to see buttons, check boxes, text fields, sliders, and radio ...