如何将计数器变量从一个函数传递到main函数

我正在编写一个程序，使用不同的算法对随机数进行排序。我已经创建了bubble_sort函数，并运行了一个测试，以确保它对数字进行了正确排序，但我想检查该函数中进行了多少交换（交换），并将这些数据返回到main。

#include <iostream>
#include <cstdlib>
using namespace std;
const int SIZE = 100;
void random_fill(int numbers[], int size);
int bubble_sort(int numbers[], int size);
int main() {
    int arr1[SIZE];
    int arr2[SIZE];
    random_fill(arr1, SIZE);
    //cout << arr1[0] << endl;
    //cout << arr1[1] << endl;
    // Copy the array contents into arr2 
    for (int i = 0; i < SIZE; i++)
    {
        arr2[i] = arr1[i];
    }
    //cout << arr2[0] << endl;
    //cout << arr2[1] << endl;
    bubble_sort(arr2, SIZE);
    for (int i = 0; i < SIZE; i++)
    {
        cout << arr2[i] << endl;
    }
}
void random_fill(int numbers[], int size)
{
    for (int i = 0; i < SIZE; i++)
    {
        numbers[i] = rand();
    }
}
void swap(int& a, int& b)
{
    int temp = a;
    a = b;
    b = temp;
}
int bubble_sort(int list_of_nums[], int size)
{
    // We will make a series of passes through the list.
    // On each pass through, we look at two numbers at a time.
    // If the second number is bigger than the first number,
    // swap the first and second number.
    // Keep making passes through the list until no more swaps are made.
    bool swap_was_made = true;      // initialize to true so we can enter the loop
    int swaps = 0;
    while (swap_was_made)
    {
        // assume no swaps will happen on this pass
        swap_was_made = false;
        // Start at the beginning of the list (position 0)
        // and start walking forward.
        for (int i = 0; i < (size - 1); i++)
        {
            // Check two numbers at a time (positions 0 and 1),
            // then 1 and 2, then 2 and 3, etc...)
            if (list_of_nums[i] > list_of_nums[i + 1])
            {
                // If the first number in position i
                // is bigger than the second number in position i + 1.
                // And remember that we made a swap!
                swap(list_of_nums[i], list_of_nums[i + 1]);
                swap_was_made = true;
                swaps++;
            }
        }
    }
    return swaps;
}

如果你能帮忙，那就太好了。