Editing For loop (section)

====Adjustment of bounds====
Just as the index variable might be modified within a for-loop, so also may its bounds and direction. But to uncertain effect. A compiler may prevent such attempts, they may have no effect, or they might even work properly - though many would declare that to do so would be wrong. Consider a statement such as
 '''for''' i := first : last : step '''do'''
   A(i) := A(i) / A(last);
If the approach to compiling such a loop was to be the evaluation of {{mono|first}}, {{mono|last}} and {{mono|step}} and the calculation of an iteration count via something like {{code|(last - first)/step}} once only at the start, then if those items were simple variables and their values were somehow adjusted during the iterations, this would have no effect on the iteration count even if the element selected for division by {{code|A(last)}} changed.