CS 100, Summer 2001
Tuesday, 7/3
Lecture 6
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Announcements: 
+ Hand in Exercise 4
+ Assignment 2 due Friday (7/6)
+ PRELIM 1 on Monday (7/9)
+ Change in consultant and office hours this week (Weds to Thurs)
+ reading: Savitch 5.1, 5.2, skim 5.3
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- Please submit lecture notes for last Friday's review session.
- Learn by doing!  Use the computer to experiment and test your
  programming skills.
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Topics:
+ do-while loops 
+ for loops 
+ Matlab
+ methods 
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+ do-while
- back to Space Invaders (demo)
EXAMPLE: read in Space Invaders scores, output avg, min, max
  - see SpaceInvadersWhile.java
+ convert to a do-while loop
  - see SpaceInvadersDoWhile.java
  - this is good if you know you're going to do something at least
    once
  - BUT note the changes we need to make sure -1 isn't treated
    as a real score
+ what if negative values are allowed as well?
  - no useful sentinel value
  - ask user how many scores they'll be entering, then count how
    many you see and stop when you've gotten all of them
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More examples of loops:
- MirrorNumberWhile.java
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for loops
+ for (init ; condition ; update) // no semicolon!
+ same as: init; while (condition) { do stuff ; update; }
EXAMPLE: convert MirrorNumberWhile.java to use a for loop:
  - MirrorNumberFor.java  
EXAMPLE: Exercise 4
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MATLAB
+ use 'help' to explore what you can do
+ a lot of information was also contained in the reading assignment
+ try 'plot'
+ use 'bar' for Assignment 2
+ to load in a text file:

  var = load('filename');

+ If you omit a semicolon at the end of a line, it shows you the value
of whatever was computed; if you put the semicolon, it suppresses the
output.  Both are useful.

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+ Methods
- think function: methodName(inputs)  ->    generates output
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Examples in Java:
  Math.random()  
  System.out.println(_stuff_);
  System.out.print(_stuff_);
  main(String[] args)
+ interesting features:
  - not all have inputs
  - some don't actually give a value (just perform an action)
+ 2 general kinds:
  - performs action without returning a value
  - returns value (and maybe also performs action)
+ more tomorrow!
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PICK UP Exercise 4 (graded)

Happy Fourth of July!