void bubble_sort(int values[], int size)
{
    // if no swaps were made we know the array is sorted
    bool swaps_made;

    // help with swaping
    int tmp;

    // don't make comparisons till the end of the array every time
    // because going through the array once "bubbles" one element to the top
    int compare_till = size - 1;

    do
    {
        swaps_made = false;
        // loop for every elemtn up to the sorted portion
        for (int i = 0; i < compare_till; i++)
        {
            // if the current element is bigger than the next one
            if (values[i] > values[i + 1])
            {
                // swap them
                tmp = values[i];
                values[i] = values[i + 1];
                values[i + 1] = tmp;

                // be sure to go through the array again next time
                swaps_made = true;
            }
        }
        // one element has "bubbled up", so make one less comparisons next time
        compare_till--;
    }
    while (swaps_made);
}