I am trying to create a while loop where a marker can't leave a box of x = -10 and y = 10, y = -10. Once the marker reaches x = 11 I want the loop to stop.

Answer 1

[Torsten]

Put the k = k+1 at the end of the while-loop, not at the beginning.

And if x(k) == -10, you only set x(k+1), but not y(k+1). This will lead to an access error for y(k+1) after k is increased by 1 for the next step.

[Voss]

To avoid that error: whatever value k has, x has to have at least k elements. That means, since you are incrementing k to k+1 on each iteration of the loop, you need to assign x(k+1) on each iteration of the loop.

But in this case x(k+1) is not assigned:

else if x(k) == -15 & y(k) == -15
    y(k+1) = y(k) + 1;
    y(k+1) = y(k) + 1;
     k = k+1

Maybe it should be this instead?

else if x(k) == -15 & y(k) == -15
    x(k+1) = x(k) + 1;
    y(k+1) = y(k) + 1;
     k = k+1