how to solve error in this user defined function?

I am trying to write a user-defined function to sort by bubble sort. My code is as follows:

void bubblesort(int arr, int n)
{
    for( int i=0; i<n-1; i++)
    {
        for( int j=0; j<n-i-1; j++)
        {
            if( arr[j]>arr[j+1])
            {
                swap(&arr[j], &arr[j+1]);
            }
        }
    }
}

The error thrown is like this: if( arr[j]>arr[j+1]) ~^ error: subscripted value is neither array nor pointer nor vector

Any ideas on how to fix it?