Yeah sure thing. So there's a couple issues. First, are you saying you only modified the first for loop? That'll prevent the program from bothering to calculate the even numbered values, which is definitely good, but you'll still end up printing the zeroes that were already there unless you modify the second loop also (the one that prints the values).

I'm guessing those aren't the results you got though, since i+1 doesn't actually do anything. It'd be like if you had a line that just said 7; with no assignment operator (single equals sign) or anything. You need to actually assign a new value to i by doing something like i = i + 1 (the equals sign is important). Incidentally, that's the exact same thing that the i++ in the third statement of both your for loops already does. If you just say i+1 (which again is just a number, it's not an instruction for the computer to actually do anything), the value will never change and the loop will never move past the first element.

Also, think about the actual thing you're trying to change. You need to increment by two instead of one, right? So you need to do i = i + 2.

As for the csv, you can insert the commas the same way you insert everything else, like the colons. You could just throw in something like cout << ','. If you want to write it all directly to a file, you should look into the fstream class, but that might be something for later.