Results are as follows:
 mytest
data length = 5
loop k = 0
loop k = 1
loop k = 2
loop k = 3
loop k = 4          <- loop stops at N-1 
data length = 9
loop k = 0
loop k = 1
loop k = 2
loop k = 3
loop k = 4
loop k = 5
loop k = 6
loop k = 7
loop k = 8
loop k = 9         <- loop goes 1 iteration too far