Understanding this design is critical because if you want to get anything done on the command line, you must be able to communicate back and forth to the user.
了解这一设计是至关重要的，因为如果需要在命令行中执行任何操作，都必须能够与用户来回通信。
2
Two design methods of fuzzy logic controller are introduced. One is graphics user interface whose control rules is certain, the other is command lines whose control rules uncertain.
Imagine the design exercise is to create a small command-line calculator: a user types (or pipes) a mathematical expression in, and the calculator parses it and prints the result.