Please suggest me some source codes to learn.

[smileff]

I have learned programming for a few years, and I have wrote codes for some projects. But these projects are not serious production projects but demos or toy projects. Thought I know a lot about common C++ grammar, I always feel I can't write good codes.

Sometimes I thought my codes are messy and I may rewrite them, but I will soon find my rewriting version is messy too. I think I should read some good codes to understand how good codes look like， as in other field, newbies often learn from masterpieces. But I don't know where to start from.

If you have read some beautiful codes which can teacher a newbies a lot, please tell me, thanks.