Ask HN: What Should I Do With Xcode?

Yesterday, I wrote some codes in C, just to develop myself. I wrote and pressed Run, I wrote and pressed..

Then I found the memory I can use is less and less. Even I closed Xcode, the memory wasn't back on its feet.

I have 4G memory. So I wander, what's wrong with it? It's my fault or something else? And what should I do?