CS99, Fall 2002
Lecture 3, Mon 9/9
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Announcements:
+ h1 due tomorrow in lab
+ h2 posted later on Tues or Weds this week (due date will account for YK)
+ remember to read on-line announcements, newsgroup, and notes
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Summary from Lecture 2
+ Problems->Solution Process->Solution
+ Process: brainstorm, research, outline, draft, polish, test
+ Outline: algorithm (sequence of instructions written in pseudocode)
+ Stepwise refinement
+ iteration and testing (haven't gotten to these yet!)
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How to go from algorithm to code? Use Computer Language:
+ need to translate English language algorithm into a computer language
+ many options: MATLAB, Maple, Java, C, C++, C#, etc
+ Choose MATLAB and Java for CS100
+ see $help lang$ for summary
+ from Help browser: 
  MATLAB->Using MATLAB->Programming and Data Types
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Language Elements
+ computer language usually written (in the future, spoken)
+ has syntax (grammar) and semantics (meaning)
+ keyboard characters (alphabet) -> tokens (words) -> statements (sentences)
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Characters
+ usually keyboard characters (ASCII text)
+ ASCII has 128 characters 
+ some are nonprinting -- see ascii.txt for full list
+ also, try entering $char(32:127)$ in MATLAB (do not enter $s: I use
  the $ notation to indicate a code fragment or statement to enter) 
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Tokens
+ characters form "words", which are called TOKENS
+ tokens include:
  numbers, operators, variables, keywords, punctuation, 
  token separators, strings, comments (described in more detail soon)
+ technically, MATLAB uses arrays for *everything*
  - arrays are collections of items
  - think "spreadsheet" for now...
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Statements
+ combine tokens to create "sentences", which are called STATEMENTS
+ each "sentence" forms an instruction/command
+ "sentences" are called statements
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