Hey, if one gets accepted to UC Berkeley for Econ, can he switch into CS. Both are in the department of Letters and Sciences. I know switching to engineering is impossible, but would switching to CS be feasible?
There is no such thing as “accepted to UC Berkeley for Econ.” If you are admitted to the College (not “department”) of L&S, you are essentially “undeclared.” Once you fulfill the requirements for a major, you can declare it.
But the first thing is that you have to be admitted to the College of L&S.
(Is this question for someone else, since another post of yours indicates that you were not admitted?)
As a frosh admit to the College of Letters and Science, you enter as undeclared and can take the prerequisites for any College of Letters and Science major. Both the economics and L&S CS majors currently require a 3.0 GPA in the prerequisites to declare.
If you start your first semester with a math course suitable for your placement, Economics 1 or 2 (may be skipped if you have a 4 on both AP economics tests), CS 10 or 61A, and a reading and composition or breadth course, then you can work toward both majors for the time being.