Java Abstract Window Toolkit (awt)
- FlowLayout: keep adding elements to GUI, maintaining position until reach next row: simple way to build window
- add(new Button("xyz")): element with text in button
- add("where", element): another way to build GUI where is “North”, “South”, “Center”, “East”, “West”
- if (" GCD: ".equals(o))
o is value from button: generally different values pick out through if else or switch ##