No I'm not a programmer at Funcom. I've been in the industry for about 12 years now so I did a bit of everything from coding to design to sound to qa and my favorite place is BY FAR in QA. Most people hate it, and most people consider it an entry-level job, something temporary before they get that big design/code job. However, I find it infinitely more fun than anything else this sad fucking shit industry has to offer. So that's what I do at Funcom. As far as video game companies go, it's by far the best job I've ever had because of how fun (heh) it is. The following doesn't necessarily apply to any specific developer I've worked for, it's mostly an amalgamation of all of them

KIDS, DONT GO INTO VIDEOGAMES. Play them, enjoy them, live in them if you want, but don't go looking for a job there. Whatever idea you have of how it is to develop AAA titles, you are dead fucking wrong

People are immature, egocentric, pretentious, there's more schoolyard politics than in an afterschool special, nobody is paid close to what they should, you'll have to throw your life away for a developer that will just fire you without as much as a how do you do when some tie-wearer wants a new set of spinners on his Audi. I've worked for half a dozen developers, all of them well known studios, and its the same shit -with slightly altered smell- everywhere.
But as for your coding question in the vaguest possible way: it depends on the project.
Most developers these work within an "Engine + Content" scheme. A "game engine" these days usually means a powerful rendering engine (with associated modeling tools) and a flexible scripting language. For example, UDK. And this engine will execute and render what is found in the content package. So you can have code programmers that work solely on shader code, network code, tools etc. And you can have content designers scripting missions for the engine, if player is here, then spawn monster there etc etc. Again, think of UDK which offers tools for art and level design too.
Now, as your project gets larger and more ambitious, you'll need to specialize teams and repeat the same process. Let's say you had the Engine Team and then the Content Team, well now inside the Engine you have Rendering and Network which become two entities entirely separate from one another, each working on different codebases. And the Content Team is now parent of the Level Design Team and the Characters Team.
All these fine people will use a concurrent versioning system of some kind. These allow you to create child copies of a master code and work on that copy 'locally'. Whenever a team has reach their goals in terms of implementation/bugfixing then they submit their changes. These get approved by leads and managers, merged into a 'internal' version of the master code, sent to QA, debugged (add some back and forth here), then when ready, merged into the 'real' master code, the out that will be put online, printed on CD, put on the appstore or whatever kind of application you're releasing.
Similar systems are used by other departments too like audio and art obviously, but they submit their work into the content portion of the game, not the code part.
All in all it looks fairly simple and efficient, but add a few dozen humans to the equation and it really just all falls apart into chaos, madness, red bull and overtime.
Stay in school, become a lawyer or something.
All that humorous ranting aside, TSW isn't perfect obviously but it's damn near well the best MMO launch in the history of MMOs so that's pretty good. A game this size will obviously have a few glitches at first but MMOs are games that are constantly evolving and changing so I'm not too worried about the game becoming only more refined in its gameplay over time.
What are you playing in TSW? I play only at work after hours for now, my current home machine being archaic, so my progression is kinda slow but I started a healer Fist build that is pretty much carrying my cabal right now and I quite enjoy it

I like how I can balance between damage and heals with the same build so I can both solo and survive easy, or focus heal my team and let the other four burn through enemies.