Moving to the "Breaking In" forum.
i want to become a game programmer . so please tell me where do i start to...?? and what kinds of thing i've to learn..??
You might want to read all of
Tom Sloper's game industry FAQs, as well as the
Breaking In forum FAQ (which largely references Tom's amazing collection).
As pointed out in several of those articles (I forget the numbers and don't see them immediately) there is no one thing to do that will lead you to your goal. Everybody has their own personal path.
We cannot tell you "Do these three steps and you'll be a professional game developer," because there are no steps that will always do it.
Most (but not all) go to college and get a degree, much like yours. A computer science degree teaches many necessary things and will also make surviving the HR filtering easier.
Many (but not all) build their own hobby games.
Many (but not all) participate in competitions and challenges to improve their talents.
Many (but not all) will have their own personal study into topics related to game development.
Many (but not all) will move to game development hubs to increase their chances of getting a job in the field.
Many (but not all) will attend game industry events, including local SIGDA and IGDA meetings, to gain contacts and experience.
Many (but not all) will participate in forums about game development.
Many (but not all) will apply to lots of jobs in the game industry.
Many (but not all) will find a job inside the game industry.
Unfortunately, some will appear to do everything 'right', they'll build a portfolio, they'll gain all the education and experience they can on their own, they'll move to a game development hub, they'll apply to every single game studio and continue applying, they'll network directly with the developers at several studios, they'll work their social network, they'll attend all the local game development meetings and get on the mailing lists and tell everyone they want a game development job .... and still struggle for years to break in. Those people are very rare, but they do exist.
For now you are in school. Getting your education should be your predominant concern. You can grow additional contacts within the game industry which will make it easier to get a job once your degree is complete. You can work on side projects related to games and participate in game development contests and build up a portfolio of hobby projects. When your degree is complete you can move to a city with many game development studios.
Until your degree is done, make education your primary focus. All the other things are secondary.