Hi,

A UI/UX designer and  a graphics designer have a completely different sets of tasks. Moreover, their fields are also different. A UI/UX Designer has the job to design the the front-end look of a website or an application, even before actual coding works starts on it. So once the functions and tasks of the application gets finalised then UI/UX is worked upon and many design are worked out. Whichever gets finalised on that the actual coding work starts.

Whereas a Graphic Designer is concerned he designs the graphics that we see on screen, be it game, art designs , logos and many other such things.

And you can do both the things if you are choosing computer science as a stream. All you need to know is to learn these skills.

Hope this helps.

Thankyou