I finally understood your problem. The problem description needs some adjustment. It is not clear that it is requesting only the global variable named 'z'. I thought it was referring to every global variable.
"global variable z" was explicitly mentioned in both the problem title and the problem description. Other than that, I trust that your comment and the Test Suite should be sufficient to remove any residual doubts.
Wheat on a chessboard pt 2
A different counting method
Comparison of floating-point numbers (singles)
Code breaker, Part II: Operation Orthos
Back to basics: adding comments to your code
Make your own Test Suite (part 1)
Just take it easy for a second or two!
Find the treasures in MATLAB Central and discover how the community can help you!
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Contact your local office