While loop crashing Unity, but is not infinite

Question

I'm aware (from similar posts) that infinite while loops are notorious for causing Unity3d to crash. I'm tring to impliment a while loop within something I'm working on, which I'm fairly sure isn't 'infinite', yet causes the game to crash.

The idea of the logic is to check a list of integers for consecutive numbers and use that as the basis to apply a bonus. The list contains 'effective shots', and has a new int added every time a shot is fired - the more consecutive effective shots, the higher the bonus.

Here's what I have:

        int count = 0;
        int firstItem = 0;
        int multiples = 3;
        int currentMultiple = 0;
        int bonusX = 0;

        foreach (int i in effectiveShots)
        {
            if (count == 0)
            {
                firstItem = i;
                count = 1;
            }

            else if (i == firstItem + count)
            {
                count++;
            }

        }

        while (count >= multiples)
        {
            currentMultiple = multiples;

            if (count == currentMultiple + multiples)
            {
                bonusX += 1;
            }

            if (bonusX > 10 || gameOver)
                break;

            UnityEngine.Debug.Log(bonusX);
        }

The logic to check for consective entries in the effectiveShots list was taken from @Jon Skeet's answer here. Though this appears to work, I think that this may be the issue. As soon as a shot is missed, count needs to be reset. Any ideas or suggestions?

The while loop should then be entered once the count of consecutive effective shots has reached the first multiple, i.e. 3 shots. Then, for every set of consequtive effective shots thereafter, increment the bonus, for example:

3 shots: bonusX = 1
6 shots: bonusX = 2
9 shots: bonusX = 3
12 shots: bonusX = 4

and repeat this until `count` is no longer >= 3, i.e. the player missed a shot.

The issue is that as soon as I hit 3 consequtive shots and enter this loop, the game crashes. I dont think I would call this an infinite loop, since missing a shot - setting count == 0 - would mean the while conditions are no longer true, so drop out of the loop (I think?). I also added an additional check to break out of the loop under certain circumstances, but this doesnt make a difference.

If you are able to give a steer as to how to fix this crashing, or have a suggestion on a better approach in general, it would be appreciated!

`yet causes the game to crash.` Can you show us a screenshot of the crash? — mjwills, Aug 08 '17 at 21:53
Your `while` loop is supposed to run **forever** as long as `count >= multiples`. You are suppose to decrement `count` in the `while` loop so that so that it becomes `< multiples`. You are **not** doing that right now. — Programmer, Aug 08 '17 at 21:53
Yeah, taking a break for 5 mins and looking at this again, it was blatantly obvious this was never going to work! I think I have a better approach at doing this, will try tomorrow and update this post with the results. Thanks all! — devklick, Aug 08 '17 at 22:14
And using a debugger, one can find the problem in less than 10 seconds once the program goes into the infinite loop. You tell the debugger to break and then check variables or step through the code **and the problem would be very obvious**. And also, it could help debug your algorithm faster. — Phil1970, Aug 08 '17 at 22:43

score 5 · Accepted Answer · answered Aug 08 '17 at 21:54

5

Nothing in your while loop changes the value of either count or multiples and so the condition will always evaluate to the same value => Infinite loop

answered Aug 08 '17 at 21:54

Mark Pim

9,898
7
40
59

I suppose it's also worth noting that this condition appears to be more rare than he expected (because it would also end the loop after evaluating to true 10 times): `if (count == currentMultiple + multiples) ` – Rufus L Aug 08 '17 at 22:05
Which is only true if `count == 6` AFAICS – Mark Pim Aug 08 '17 at 22:07

While loop crashing Unity, but is not infinite

1 Answers1