Error Types and Debugging

Two major types of errors:
Syntax errors - grammar, spelling, wrong number of arguments

Easy to find and fix - Modern editors (like MATLAB's) highlight
errors and warnings (underline in red and yellow)

On a program crash the Command Window provides the line number so they
are easy to find

Semantic errors - logical errors, errors in meaning, program runs but does not
do what is intended

Harder to find and fix - Editors can't identify issues because they don't know
what the programmer wanted

Programmer needs to know the correct behavior of each piece of code

Need to know what the contents of variables should be throughout the execution


Debugging - done to methodically find where errors are
Debugging Techniques:
	incremental coding to avoid making errors to begin with and/or detect early (as soon as you make them)
	comment out selected portions of the code
	display messages / variable values while code is running by
	unsuppressing output / adding fprintf or disp statements
	find smallest example that causes the problem
	using a debugger

A debugger is a programming tool that assists in debugging code
Basic functionality:
Set breakpoints (stop executing code & wait)
Step through (execute) code line by line
	Step over (skip over executing a function), into (go into a function), out of (go out of a function)
	Continue to next breakpoints
View contents of key variables (in Workspace) when code has stopped executing

MATLAB specific:
Icons at the top of editor ribbon: Breakpoints, Continue, Step, Step In, Step Out, Quit Debugging
In editor window: Breakpoints on left side (right click to set/change conditions), arrow shows line
about to execute.
Workspace: Shows variables at current point in execution

Example on laptop: Use validateID