CS 100, Summer 2001
Monday, 7/2
Lecture 5
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Announcements: 
+ Pick up (graded) Assignment 1
+ Exercise 4 due Tuesday (7/3)
+ Changes:
  + Assignment 2 due Friday (7/6)
  + PRELIM 1 on Monday (7/9): covers Savitch Ch.1-3
+ reading: Savitch ??
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- Assignment 1: scores/errors/etc.
  + average: 38 (out of 50)
  + note that most people in the class will receive A's and B's.
  + 5 people got the bonus point - good job!
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Practice predicting output (important for Prelim 1):
- savitch self-test Ch. 2 {7, 9, 10, 12}, Ch. 3 {7-9, 11-13, 17, 19, 21, 27-29}
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Topics:
+ debugging
+ while loops
+ do-while loops
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Testing/Debugging
+ methods:
  1. compile the code (computer feedback)
  2. try different values to see if you can "break" it
	- alpha testing vs. beta testing
  3. verbally describe the algorithm to a friend (highlight 	assumptions!)
  4. simulate on paper by hand
  5. CodeWarrior debugger (breakpoints, variable watching): more on 	this later in the course
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+ while loop
- Syntax: how to write the while loop
  while (condition)
  {
    // loop body
  }

Visual diagram:
	Start
	  |
	  v
/-> Check cond
|    T/   \F
\-Do body  exit

+ executes 0 or more times
+ sentinel values: "invalid" values to signal the end of input
EXAMPLE: read in Space Invaders scores, output avg, min, max
- see SpaceInvadersWhile.java
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Another form:
+ do-while loop 
- Syntax: how to write the while loop
  do
  {
    // loop body
  } while (condition); // note semicolon is required here!

Visual diagram:
	Start
	  |
	  v
/->   body
|       |
|       v
|   check cond
|    T/   \F
\----/    exit

+ note: executes 1 or more times
- see SpaceInvadersDo.java (compare to previous version)
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(this should have been be lecture notes from Thursday (6/28)!)
infinite loops (bad)
+ how stop in code warrior? ^C
+ what about operating systems? (e.g. Windows)
+ infinite loops can be useful.  But we'll mostly avoid them here.
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PICK UP Assignment 1 and Exercise 3 (graded)
PICK UP Assignment 2 and Exercise 4 (handout)