for a MATLAB class

this is one problem, just cut off on one page

7. Given an array of numbers that could be negative, write a function posavg(a) to calculate and return the average (mean) of the non- negative numbers in the single dimensional array, a. One such solution is mean(a(find(a>0))). In order to test your understanding of class concepts, re-implement the posavg(a) function using iteration. You may not use the built-in functions sum(...), find(...), or mean(...) in your solution. I bould l