Can someone explain how these input statements are handled in c++?

I will start off by honestly stating that this has to do with homework, but the question I need to ask by no means gives me a direct answer to the problem i am having trouble with (I can post the problem if you don’t trust me.) I am having trouble understanding what these input statements specifically do as I have vary rarely used c++ input of this type. What is happening for each of these statements:

cin >> sclr >> vec[2*i-1] >> mat[f(i)][j+k] >> t[i/3][j][k];

I need to understand what the last three statements mean in terms of c++ just so that I can actually start the problem i am on. If I had time I would just ask the teacher for clarification but alas I do not. I would greatly appreciate it if some of you c++ gurus could take a minute to explain this to me.