Non-self explanatory aspects of the graphic user interface should be documented, with sketches if appropriate. In this course highest priority will be given to correctness and clarity . For example, we won't mind if a program crashes when the user makes a mistake and enters a real when a character is expected. On the other hand, since this is a course on geometry, we'll expect no geometric errors. For example, a program to intersect lines must not crash and must do something sensible when the input lines are parallel.
Clarity is very important in programming.
A program should begin with a description of what it does and how it does it. Similar remarks apply to each procedure. Use mnemonic variable and procedure names, use upper and lower case characters in your code, explain what variables mean, comment programs liberally. Comments will help us, but they'll help you as well. Do not forget to put your name in your files.