What is wrong with my bubble sort implementation?

Question

I implemented a bubble sort solution for pset3-sort. It works when I call the function from a test file I made, but when I print out the values of values in find.c it gets printed out unsorted.

I've been into this now for two days and just can't seem to understand where I'm going wrong as it works fine in the test file I made which calls and passes the exact same values find.c does.

Here's my code section for reference:

void sort(int values[], int n)
{
    int swapped = true;
    while (swapped == true)
    {
        swapped = false;
        for (int i = 0; i < n - 1; i++)
        {
            if (values[i] > values[i+1])
            {
                int temp = values[i+1];
                values[i+1] = values[i];
                values[i] = temp;
                swapped = true;
            }
        }
    }
}

Any help would be much appreciated!

Answer 1

Without seeing the data that you're feeding it, it's impossible to say precisely what's happening. It's possible that your test program data set is demonstrating a success, or a partial success, while other data might not.

Having said that, there's actually a problem with your sort. You pass it an array with N elements to be sorted. However, you are sorting N + 1 elements! In other words, you're going past the end of the array. When you do this, you are introducing garbage data into the sort, so the result is unpredictable.

In real terms, let's say that N=5. As the sort progresses to the end of the array, it will end up looking at values[5] and values[6] and comparing them, as well as sorting the values stored there with the other values in the array. The problem is that the array range is from 0 to 4. Big problem.

Also, without seeing how the calling code and data, both in your test program and in find.c, I can't see if there are other problems.

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