CS141: Topics for Sept 23, 25 & 27, 2013

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Homework and Reading

The reading and homework for this week can be found here: Lab 5: Loops

Vocabulary

For practice, check out the WileyPlus Chapter 5 Flash Cards!

method (function, member function, procedure) black box modularization stepwise refinement (revisited) reusability return type, return value

(formal) parameter variable argument (actual parameter) parameter passing variable scope: local, global tracing code stub recursive methods

Common expressions are:

"call a method" or "call a function"
"return a value"
"pass a value as a parameter"

Topics: Chp 4 - Loops (topics still to cover)

• You should soon complete: BlackJack Part 1. In preparation for Part 2 of the lab, try to better organize your code. That is, identify each of the actions that need to be done:
  1. Prompting
  2. Picking a card index
  3. Calculating the suit and face indices,
  4. Determining the name of the suit and face
  5. Printing the full name of a card
  6. Prompting again
  Try to write code where each action is done in a different section of the code.
• Types of loops: do-while-loops - checks condition at end; always executes the body at least once
• Figuring out what is going on - Hand tracing, unraveling the loop
• Book examples: max values, min values, comparing adjacent
• Nested loops. See Nested Loop Problems (pdf)
• Random numbers and games- rolling a die, picking a card.
• Monte Carlo method

Topics: Chp 5 - Methods

• What are methods and why do we want them? E.g. Math.round, rolling a die.
• Why use methods?
  • reusability
  • modularity and testing
  • structure and readability
• Look at the structure of Part 1 of the BlackJack game.
• Light-bot
• Components of a Method Declaration
  • header (first line, aka the method signature) - contains the return type, method name, parameter list
  • method body
  • If the return type is not void, the method body must contain a return statement
  • Terminology:
    • declare or write a method
    • call a method
    • arguments (actual parameters) vs formal parameters
    • passing in a parameter (argument)
• Tracing the code - stepping through the code line-by-line. Do you understand the order the statements are executed?
• Scope - see problem in previous Exam 2
• Writing code using stepwise refinement - methods make this easy to do.
• Stubs
• Recursive methods - looping without loops or solving the towers of hanoi

In Class Practice Activities

• Nested Loop Problems (pdf)
• Practice writing methods and learning the terminology Basic Method Problems (pdf)
• Practice with scope Scope (pdf)
• Discuss the rest of the BlackJack program.

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