CS 448 Lecture - coding/debugging

1. "Any system that will make the same mistake forever is not intelligent".  JHHolland
2. Programming
   • Threads
     • Foo extends Thread
     • public void run()... while(true)... the Thread exists until run exits
     • Foo myFoo = new Foo();... myFoo.start() (spawns a Thread and sends it run())... myFoo.join(); suspends until myFoo ends...
     • Similarly: repaint() schedules update(Graphics) in 100 msecs... if no other repaint() happens before that, it happens
   • Image buffering
     • Create an image (Components know how)
     • Get it's graphics context (Graphics offScreenG = theImage.getGraphics())
     • When painting it, paint to offScreenG
     • Then, after all the painting is done, drawImage(theImage)
   • Debugging - part of the skill of programming is having faith you can find any bug (eventually)
     • Analysis ; if that works, done, else
     • add diagnostic output; if that shows the problem, done, else
     • use the debugger... breakpoints, stepping, stacktrace, values of variables
     • create the problem in a simpler context...
     • write test code
     • formulate hypotheses and test them (when all else fails use the scientific method!)
3. Compared to what?
   • Different ways to compare: best value, average value, best individual in: CPU-time/generations/evaluations
   • random (or enumeration)
   • mutation only
   • bit-climbing
4. Fitness functions
   • ONES
   • FOUR
   • VEHICLES