CS99 Fall 2002
Prelim 1 Topics

Problem Solving
+ programming is automating problem solving
+ process (brainstorm, research, outline, draft, polish, test)
+ algorithms for outlining
  - definition: sequence of steps to solve a problem
  - must be general enough to implement in most languages
+ programming converts human algorithm into computer code

Languages
+ computer language needed for code
+ similar features of human languages
  - alphabet (keyboard characters)
  - words (tokens that use characters)
  - sentences (statements, which are instructions written with tokens)

MATLAB language (MATrix LABoratory)
+ tokens: 
  white space, token separators, punctuation, operators, numbers, 
  strings, comments, identifiers, keywords, functions, arrays
   (actually, EVERYTHING in MATLAB is technically an array)
+ statements:
  - empty, expression, function, assignment, selection
  - repetition not on this test
  - punctuation: , (for same line but not suppress output)
                 ; (suppress output)
                 hitting RETURN

Expression statement
+ expression combine values, operators, functions
+ operator precedence, associativity
+ MATLAB outputs result of expression unless you suppress output with
  semicolon (;)
+ use parentheses to clarify order of desired operations

Assignment statement
+ must give a variable a value before using it
+ MATLAB is weakly typed -- does not require you to indicate a variable's type
  (everything is technically an array, anyway)
+ assignment syntax: name=expression
+ to clear an assignment use clear or clear name

Function statement
+ name(parameters) causes MATLAB to
  - look for a function called name
  - do the commands written inside the function called name
+ so, functions are like separate mini-programs
+ a function that returns a value is replaced by that value in an expression
  ex) 1 + sqrt(4) is replaced by 1 + 2 which is evaluated to 3

Selection statement
+ need to make choices
+ use if-elseif-elseif...-else-end
+ only if and end are necessary
+ syntax: if c
             s
	  end
+ c is a boolean expression
  - rem: 0 is false, and any other number (esp 1) is true
  - expression composed of logical values (0,1), logical operators
    & (and) | (or) ~ (not), and relations
+ s is a block of statements
  - each statement executes if the condition is true
  - when end reached, statement stops
+ can have as many elseifs as you want
+ only one else is allowed
+ shortcut notation:
  put everything on same line and separate with commas
+ nested ifs
  - can make choices within choices
  - makes a compound statement

While loops
+ while(c), statements, end syntax
+ tracing variable values in a while loop
+ loops to produce repeated values

Not on exam:
+ plotting
+ logical arrays