how do I fill this array without overwriting?

Question

I've ran into a seemingly simple problem but I can't figure out how to do it. I want to fill the second column in an array of 32 rows and 4 columns like this: 1,1,2,2,3,3,...,16,16. And, I want to use an already-existing loop where the counter goes from 0 to 15. So each time I want to write on two elements without that element being overwritten in it's following loop. I did this: array[4*i+1]=i+1; array[4*i+5]=i+1; But then array[4*i+5] is being overwritten in the next loop. How should I do this?

Answer 1

You actually want your math inside the array to be as follows:

 array[8*i+1]=i+1;
 array[8*i+5]=i+1;

since you are actually moving through 2 rows x 4 columns = 8 per iteration