Lecture Four -- Outline

Learning Objectives

• We have a style guide, use it!
• How to write good test cases of your own
• Problem solving - lots of ways to solve the same problem

Announcements

• Ant man - what time do you need to leave recitation?
• Read the write-up carefully
• HW4 -- will be released today, due Monday (unless it's very stressful, then it will be due Tuesday)
• Piazza Posts - read them :)
• No office hours Friday nights
• Lending Library -> Check out some of my books!
• Lecture feedback -- let's make lecture better!
  • Positive Learning Environment
  • More fun stuff + applications to functions
  • List of functions written in lecture after lecture
• Quiz on Monday
  • Structure will be 2 CT's, 1-2 ROC's, and 2 FR
  • FR worth the most points, do those first
  • CT and ROC are fully answer based, show your work
  • Lots of practice on the website

Lecture Plan

• [9:00] Announcements
• [9:05] Leftovers from yesterday
  • split and splitlines
  • string formatting
  • file i/o

• [9:10] Magic Trick

  • Parity Bit -- error checking

• [9:15] Style, Testing and Debugging -- why do we care?

  • Famous Software Bugs

• [9:20] Style
  • Make fun of Tara's hw1.py with no comments or well-named variables
• [9:30] Writing Test Cases
  • Let's catch a buggy testPigLatin
  • Console/Graphics -> don't worry about this for now
  • Exceptions (from course notes)
• [9:45] The 3 different types of errors
• [9:50] Debugging Strategies
  • Avoiding bugs
    • Good style!
    • Write tests before you code
    • Each function has one task
    • Copy/pasting == bad
      
  • In general
    • Read the error message + line number
    • Bottom of stack trace
  • Syntax Errors (see course notes)
    • Where is the arrow pointing?
    • Forgetting a colon, indent, parenthesis, quote, = instead of ==
    • When can this be tricky?
  • Runtime Errors
    • String/index errors
    • Typo in variable name
    • Infinite loops
    • Operation on an inappropriate type
    • Dividing by 0
    • Reading a file that doesn't exist...
      
• [10:00] Practice Free Response -- encodeRightLeftCipher
  • If there is time, how would we decode this?
• [10:18] Attendance Check

HW4

• Released today!

Up Next

• Lists!