Do computer programer/software engg use these topics in practical job:DiscreteMaths,DataStructur…

I’ve just finished my graduation in Maths from DU. I’m now really confused whether I should go for MCA or not. See, in cl 12, I was exceptionally good in computer programming (we had C++ then) and was sure I wanted to take that up as a career. But, the engineering courses were extremely theory based and had a variety of other subjects like Digital Design, Probability and Statistical Methods, Discrete Mathematics Mathematical Foundations of computer Science, and core programming formed only 5 % of the syllabus.Thus I decided to do Maths from D.U. It is now time for me to choose a career and I don’t want to let my talent for programming go waste. Please tell me if the above topics which I found too theoretical and disliked are of any importance to computer programers or software engineers. Also, what exactly does a programmer/software engineer do once he joins a company. Is his job only converting things into source code?Please help me out as Im terribly puzzled..